Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 2 of 45 

LIST OF TABLES 

4.1.1-1 Summary of air monitoring data from stations at and surrounding the Y-12 

facility ..................................................................................................................................11
 

4.1.2-2 Uranium air concentration data measured at the twelve y-12 air 

monitoring stations..............................................................................................................13
 

4.2.3-1 Annual average air concentrations and estimated Chi/Q values for Y-12 

Station 2..............................................................................................................................20
 

4.2.3-4 Annual average air concentrations and estimated Chi/Q values for Y-12 

Station 4..............................................................................................................................21
 

4.2.3-8 Annual average air concentrations and estimated Chi/Q values for Y-12 

Station 8..............................................................................................................................22
 

4.2.3-12 Annual average air concentrations and estimated Chi/Q values for Y-12 

Station 12............................................................................................................................23
 

4.2.4-1 Compiled uranium release estimates..................................................................................24
 

D-1 Calculated 234/235U and 238U air concentrations and intakes for Station 2............................39
 

D-2 Calculated 234/235U and 238U air concentrations and intakes for Station 4............................40
 

D-3 Calculated 234/235U and 238U air concentrations and intakes for Station 8............................41
 

D-4 Calculated 234/235U and 238U air concentrations and intakes for Station 12..........................42
 

D-5 Site wide 234/235U and 238U air concentrations and Intakes based on 

average air concentrations for Stations 2, 4, 8 and 12........................................................43
 

D-6 Maximum 234/235U and 238U air concentrations and intakes .................................................44
 

LIST OF FIGURES 

4.1.2-1 Locations of ORNL Perimeter Air Monitoring (PAM) Stations ...............................................8
 

4.1.2-2 Location of Station 40 incorporated into the ORNL Perimeter Air 

Monitoring (PAM) network in 1983........................................................................................9
 

4.1.2-3 Locations of the twelve Y-12 perimeter air monitoring stations...........................................10
 

4.2.4-1 Distribution of release estimates for the Y-12 facility ..........................................................17
 

4.2.5-1 Plot of annual total uranium air concentration measured at Station 2 

verses estimated uranium releases ....................................................................................17
 

4.2.5-2 Plot of annual total uranium air concentration measured at Station 4 

verses estimated uranium releases ....................................................................................18
 

4.2.5-3 Plot of annual total uranium air concentration measured at Station 8 

verses estimated uranium releases ....................................................................................18
 

4.2.5-4 Plot of annual total uranium air concentration measured at Station 12 

verses estimated uranium releases ....................................................................................19
 

4.3-1 Locations of Y-12 perimeter air monitoring stations............................................................26 

4.3-2 Distribution of 234/235U and 238U release estimates for the years 1985 

through 1995.......................................................................................................................25 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 3 of 45 

RECORD OF ISSUE/REVISIONS 

ISSUE 

AUTHORIZATION 

DATE 

EFFECTIVE 

DATE 

REV. 

NO. DESCRIPTION 

Draft 10/03/2003 00-A New document to establish Occupational 

Environmental Dose, Section 4. Initiated by 

William E. Murray. 

Draft 11/10/2003 00-B Incorporates comments from NIOSH and internal 

review. Initiated by William E. Murray. 

Draft 11/25/2003 00-C Incorporates comments in response to NIOSH 

email of 11/24/2003. Editorial comments from 

previous review have been incorporated into text. 

Initiated by William E. Murray. 

12/05/2003 12/05/2003 00 First approved issue. Initiated by William E. 

Murray. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 4 of 45 

ACRONYMS AND ABBREVIATIONS 

ASER Annual Site Environmental Report 

Bq becquerel 

cm centimeter 

CEDR Comprehensive Epidemiologic Data Resource 

Ci curie 

DOE Department of Energy 

DU Depleted Uranium 

EU Enriched Uranium 

EPA Environmental Protection Agency 

FP Fission products 

g gram 

GM Geometric mean 

GSD Geometric standard deviation 

h hour 

kg kilogram 

LAM Local area monitoring 

m meter 

MMES Martin Marietta Energy Systems 

NESHAP National Emission Standards for Hazardous Pollutants 

ORAU Oak Ridge Associated Universities 

ORDR Oak Ridge Dose Reconstruction 

ORGDP Oak Ridge Gaseous Diffusion Plant 

ORNL Oak Ridge National Laboratory 

ORO Oak Ridge Operations 

ORR Oak Ridge Reservation 

OSTI Office of Scientific and Technical Information 

PAM Perimeter air monitoring 

RAM Remote air monitoring 

TDEC Tennessee Department of Environment and Conservation 

TRU Transuranics 

Y-12 Y-12 National Security Complex 

y Year 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 5 of 45 

μCi microcurie 

μg microgram 

μR microroentgen 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 6 of 45 

4.1 Introduction 

The occupational environmental dose received by unmonitored workers is limited to exposures 

received while outside buildings and within the perimeter of the Y-12 National Security Complex. 

Buildings and other operational units occupy the vast majority of the land area at Y-12. This 

assessment will quantify exposure for unmonitored workers who either work outdoors or otherwise 

spend time outside buildings. Based on the exposure assessment, the two exposure pathways are: 

1. Inhalation of uranium in ambient air due to operational releases, 

2. Direct external radiation from radionuclides in soils and outdoor surfaces, as well as shine 

from buildings and operational units. 

Due to the complexity of the terrain surrounding Y-12 and the release mechanisms from the 

production facilities compounded by the limited dispersion distances, traditional dispersion and 

transport models were considered unsuitable. An empirical approach based on the limited ambient air 

monitoring at Y-12 was used to estimate uranium air concentrations. This approach used the annual 

release estimates independently reconstructed by previous studies to generate annual air 

concentrations for four locations within Y-12. 

External exposures were estimated using the results of a comprehensive radiological scoping survey 

(Foley and Carrier 1990). The analysis of the results from the scoping survey generated a statistical 

range of exposure values. 

4.1.1 Ambient Air Monitoring at Y-12 

A review of the history of environmental monitoring was conducted of the historical ambient air 

monitoring data at Y-12. The quality of collected data was then evaluated to assess its usability for 

the purposes of evaluating intakes by workers. The review identified likely sources of information for 

ambient air monitoring data for both the Oak Ridge Reservation (ORR) and Y-12 . Relevant reports 

were identified from a number of libraries including the: 

•	 Comprehensive Epidemiologic Data Resource (CEDR) maintained by the U.S Department of 

Energy (DOE), 

•	 Energy Citations Database, developed by the DOE, Office of Scientific and Technical 

Information (OSTI), 

•	 Oak Ridge Associated Universities (ORAU), 

•	 Oak Ridge National Laboratory (ORNL), 

•	 Oak Ridge Annual Site Environmental Reports (ASER), and 

•	 DOE Oak Ridge Operations (ORO) Public Reading rooms. 

In addition, discussions with persons familiar with the environmental monitoring activities at Y-12 and 

the Oak Ridge Reservation were conducted to identify other likely sources of information. 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 7 of 45 

4.1.2 Chronology of Ambient Air Monitoring Activities 

As the Y-12 facility has been operational for many years, there is no single source of ambient air 

monitoring information. This section presents a brief summary of ambient air monitoring activities 

specific to Y-12. No information on ambient air monitoring prior to 1959 was identified that was useful 

for this section. A detailed summary of air monitoring data including the source of information, the 

period of coverage, the type of available data, and the monitoring locations is presented in Table 

4.1.2-1. 

1959 – 1970: Applied Health Physics and Safety Reports 

A series of Applied Health Physics Reports were identified that were published by the Health Physics 

Division of the ORNL. These reports were issued on a quarterly basis (entitled “Environmental Levels 

of Radioactivity for the Oak Ridge Area”) and summarized in annual reports (“Applied Health Physics 

and Safety Annual Reports”). Data collected by the team may have been from either source (or both) 

as not all reports were readily available. The air concentrations presented in these reports were 

collected from a system of air monitoring stations established and maintained by ORNL. These 

stations were used to provide data in determining the dispersal of contamination should a major 

incident occur. A review of the data presented in these reports indicates that the purpose of these 

stations was to monitor the concentrations of fission products from operations at ORNL. 

There were three networks of monitoring stations initially established by ORNL: 

1. A system of ten stations was located within the perimeter of ORNL: Local Air Monitoring 

(LAM) network. 

2. Seven stations were initially established around the ORR known as the Perimeter Air 

Monitoring (PAM) network. The number of stations within the PAM was later increased to 

nine. 

3. A third system of eight stations was established at distances of 12 to 120 miles from ORNL; 

this system was known as the Remote Air Monitoring (RAM) network. 

Prior to 1983, the closest air monitoring station to Y-12 was the Midway Gate station which was part 

of the ORNL PAM network. This health physics station, initially designated as HP-12 (later renamed 

HP-32), was located north of the intersection of Bear Creek Road and Lafayette Drive (Figure 4.1.2­

1). A second station (HP-11) was located on Bethel Valley Road (Kerr Hollow). This station is far 

removed from the Y-12 facility and it is unlikely to provide relevant data. These stations are the only 

known locations for ambient air monitoring data in the vicinity of the Y-12 facility prior to 1983. 

Samples were collected at HP-12/HP-32 by passing air continuously through a filter paper which 

would only accumulate particles considered to be respirable. Sample collection frequency varied 

during this period. However, most of the samples were collected weekly. Estimated concentrations 

were compared to maximum permissible concentrations to determine if further analyses were 

warranted. 

Earlier available data for this station (HP-12/HP-32) were characterized as “Activity” or as “Long-lived 

Activity.” No further characterization was available in the published reports. Gross β data was first 

available in 1963 and gross α results were first reported in 1965 (Table 4.1.2-1). 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 8 of 45 

Figure 4.1.2-1. Locations of ORNL Perimeter Air Monitoring (PAM) Stations. Station HP12 at Midway Gate (later renamed HP-32) is the closest station to the Y-12 facility prior to 

1983 (Abee 1961). 

1971 – 1983: Environmental Monitoring Reports 

This series of reports covers all the ORR facilities and the stations initially established by ORNL. A 

number of new stations established north of Y-12, were used to measure fluorides, sulfur and dustfall. Station HP-32 (previously designated HP-12) at the Midway Gate continued to be the only health 

physics monitoring station closest to Y-12. Data collected and presented in these reports for HP-32 

(Midway Gate) was limited to gross α and gross β as shown in Table 4.1.2-1 and a detailed analysis 

was performed only if the concentrations were above established maximum permissible 

concentrations. 

Uranium activity in air was reported beginning in 1975. However, the reported concentration was 

based on a composite sample taken from all stations with the PAM network. In 1975, high 

concentrations of ambient uranium were noted and were attributed to enrichment and processing 

activities at the Oak Ridge Gaseous Diffusion Plant (ORGDP) and Y-12. The elevated 

concentrations also noted in 1976 were attributed to operational problems with the pollution control on 

the purge cascade at ORGDP. Since these values were averaged for all PAM stations, no direct 

relationship to the operations at Y-12 could be made from these data sets. It is likely that data 

specific to Station HP-32 were collected. However, these data were not reported in any of the reports 

reviewed. 

Two changes in the air monitoring network were noted in 1983: 

1. A second monitoring station was established east of Y-12. This station initially designated HP40 (later re-designated Station 40) was located along Bear Creek road at the northeast corner 

of the perimeter of the Y-12 facility (Figure 4.1.2-2). Samples collected at this station were 

analyzed for gross α and gross β activity and iodine-131 (131I), along with other radionuclides 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 9 of 45 

including fission products (FP), uranium and transuranics (TRU). These concentrations were 

averaged for all stations in the PAM network. 

2. The second major change was the establishment of the eleven air monitoring stations in and 

around the perimeter of Y-12. These stations were established primarily to measure uranium. 

The location and operation of these stations is further described in the next section. 

Figure 4.1.2-2. Location of Station 40 incorporated into the ORNL Perimeter Air Monitoring 

(PAM) network in 1983. Station is located at the northeast perimeter of the Y-12 facility (DOE 

2002). 

1984 – 1999: Annual Monitoring Report / Annual Site Environmental Report 

After 1984, the amount of environmental monitoring increased substantially and this period is the most 

significant for uranium air monitoring at Y-12. The air monitors established in and around the Y-12 

perimeter, which began operations in 1983, were primarily for the measurement of uranium. 

Sampling for radioactive particulates was conducted by passing air continuously through filter papers. 

These filters were evaluated weekly for gross α and gross β activity. The filters were composited 

quarterly and were evaluated for four uranium isotopes (234U, 235U, 236U and 238U). Reports from 1988 

onward indicate that the filters were analyzed using alpha spectroscopy. No information on the 

analytical techniques employed before 1988 was immediately available. The Y-12 perimeter stations 

were increased to 12 stations beginning in 1985. The location of these stations is shown in Figure 

4.1.2-3. 

Note that for 1985 and 1986, these stations were initially designated as A61 through A71. A twelfth 

station (Station 12, formerly A72) was added in 1985; however, this station was initially used to 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 10 of 45 

measure suspended particulates. Ambient uranium measurements at this station did not commence 

until 1987. With the establishment of the twelfth station, these stations were re-designated as Y-12 

Figure 4.1.2-3. Locations of the twelve Y-12 perimeter air monitoring stations (DOE 1990) 

Stations 1 through 12. Ambient uranium data for the twelve Y-12 stations included gross α and gross 

β and activity concentrations (μCi cm-3) for four uranium isotopes (234U, 235U, 236U and 238U). 

In 1993, the analysis program for radionuclides was revised to obtain total uranium (μg m-3) 

concentrations and the percentage of 235U. This approach was implemented to better correlate air 

concentrations with the stack emission data that were measured in terms of uranium mass. As shown 

in Table 4.1.2-2, data subsequent to, and including 1993, are reported in terms of μg m-3 . 

Since there were no Federal or State regulations, or DOE Orders that required the monitoring of 

uranium releases, and with the reduction of plant operations, the usefulness of the Y-12 stations was 

re-evaluated in 1993. With the installation of an ambient air monitoring station at the Scarboro 

community (located north of Y-12), the Y-12 stations were considered redundant. In addition, 

processes that resulted in the emission of enriched and depleted uranium were equipped with stack 

samplers that were reviewed and approved by the Environmental Protection Agency (EPA) to meet 

the requirements of the National Emission Standards for Hazardous Air Pollutants (NESHAPs) 

regulations. Therefore, sampling at all but three of the stations (4, 5, and 8) was discontinued after 

1994. 

2001-2002: Tennessee Department of Environment and Conservation 

With an agreement reached with the Tennessee Department of Environment and Conservation 

(TDEC), TDEC personnel took over responsibility for sampling and analysis of the remaining three 

uranium air sampling stations. 

Samples collected from the three remaining Y-12 Stations (4, 5 and 8) by TDEC are only analyzed for 

gross α and gross β. Gamma spectrometry was performed only on samples that exhibited elevated 

gross results. Consequently, uranium air concentrations were no longer available after 1999. 
Table 4.1.2-1. Summary of air monitoring data from stations at and surrounding the Y-12 facility. Year Reference Off site health physics stations1 Y-12 on site air monitoring sta

Activity/fission products Gross α Gross β Uranium isotopes2 Gross α Gross β Uranium isotopes2 Total u

activity 

1959 Abee 1960a HP-12 — — — — — — 1960 Abee 1960b, Abee 1961, ORNL 1960 HP-12 — — — — — — 

1961 ORNL 1962 HP-12 — — — — — — 

1962 ORNL 1963 HP-32 — — — — — — 

1963 ORNL 1964a, ORNL 1964b HP-32 — HP-32 — — — — 1964 ORNL 1965a, ORNL 1965b — — HP-32 — — — — 1965 ORNL 1966b HP-32 HP-32 HP-32 — — — — 

1966 ORNL 1967c, ORNL 1967a HP-32 HP-32 HP-32 — — — — 1967 ORNL 1968c, ORNL 1968a HP-32 HP-32 HP-32 — — — — 1968 ORNL 1969a, ORNL 1969b, ORNL 1969c HP-32 HP-32 HP-32 — — — — 1969 ORNL 1969d, ORNL 1969e, ORNL 1970 HP-32 HP-32 HP-32 — — — — 

1970 ORNL 1971 HP-32 — — — — — — 

1971 UCC 1972 — HP-32 HP-32 — — — — 

1972 UCC 1973 — HP-32 HP-32 — — — — 

1973 UCC 1974 — HP-32 HP-32 — — — — 

1974 UCC 1975 — HP-32 HP-32 — — — — 

1975 UCC 1976 — HP-32 HP-32 PAM Composite3 — — — 

1976 UCC 1977 — HP-32 HP-32 PAM Composite3 — — — 1977 UCC 1978 — HP-32 HP-32 PAM Composite3 — — — 1978 UCC 1979 — HP-32 HP-32 PAM Composite3 — — — 1979 UCC 1980 — HP-32 HP-32 PAM Composite3 — — — 1980 UCC 1981 — HP-32 HP-32 PAM Composite3 — — — 1981 UCC 1982 — HP-32 HP-32 PAM Composite3 — — — 1982 UCC 1983 — HP-32 HP-32 PAM Composite3 — — — 1983 MMES 1984 — HP-32 and HP­ 40 HP-32 and HP­ 40 PAM Composite3 — — — Y-12 S

1 

1984 MMES 1985 — Station 40 Station 40 PAM Composite3 — — — Y-12 S

1 
 Table 4.1.2-1. (Continued) 

Year Reference 

Off site health physics stations1 Y-12 on site air monitoring sta

Activity/fission 

products Gross α Gross β 

Uranium 

isotopes2 Gross α Gross β 

Uranium 

isotopes2 

Total u

activity 

1985 MMES 1986 — Station 40 Station 40 PAM 

Composite3 

Y-12 Stations: 

1 -11 

Y-12 Stations: 

1 -11 

Y-12 Stations: 

1 –11 

1986 DOE 1987a, DOE 

1987b 

— Station 40 Station 40 Station 40 Y-12 Stations: 

1 -11 

Y-12 Stations: 

1 -11 

Y-12 Stations: 

1 -11 

19874 DOE 1988a, DOE 

1988b 

— Station 40 Station 40 Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

1988 DOE 1989 — Station 40 Station 40 Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

1989 DOE 1990 — Station 40 Station 40 Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

1990 DOE 1991 — Station 40 Station 40 Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

1991 DOE 1992a, DOE 

1992b 

— Station 40 Station 40 Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

19925 DOE 1993a, DOE 

1993b 

— — — Station 40 Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

Y-12 Stations: 

1 –12 

1993 DOE 1994 — — — PAM 

Composite3 

— — — 

1994 DOE 1995 — — — Station 40 — — — 1995 DOE 1996 — Station 40 Station 40 Station 40 — — — 

1996 DOE 1997 — Station 40 Station 40 Station 40 — — — 1997 DOE 1998 — Station 40 Station 40 Station 40 — — — 1998 DOE 1999 — Station 40 Station 40 Station 40 — — — 1999 DOE 2000 — — — Station 40 — — — 

20006 DOE 2001 — — — Station 40 Y-12 Stations: 

4, 5, and 8 

Y-12 Stations: 

4, 5, and 8 

— 

20016 DOE 2002 — — — Station 40 Y-12 Stations: 

4, 5, and 8 

Y-12 Stations: 

4, 5, and 8 

— 

NOTES 1. Station HP-12 was the initial designation for the ORNL Perimeter Air Monitoring (PAM) Station at the Midway Gate, located northeast of Y-12. After 

renumbered HP-32. After 1984, HP-12 was relocated closer to Y-12 and was re-designated as Station 40. Y-12 Stations 1 - 12 (initially designated around Y-12 . 

2. Isotopes measured were 234U, 235U, 236U and 238U. 

3. Ambient air concentrations only reported as an average for ALL stations within the PAM network. 4. Units used for uranium data presented in Volume 1 of the 1987 report (DOE 1988a) are incompatible with similar data presented in Volume 2 for the 

Error is most likely due to units used in Volume 1 as units used in Volume 2 are consistent with preceding and proceeding years. 

5. Incompatibility of data values between annual average uranium concentrations presented in Volume 1 of 1992 Annual Site Environmental Report (D

presented in Volume 2 of same year (DOE 1993b). No Errata were found for this year. Therefore, the averages presented in Volume 1 were used. 

for U-235 from volume 1. Average is calculated from quarterly data presented in Volume 2. 

6. Responsibility for Y-12 stations 4, 5 and 8 was transferred to the Tennessee Department of Environment and Conservation (TDEC). Samples collec

and gross β only. Uranium analysis is only performed if gross measurements are elevated. 
 

 

 

 

 

 

 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 13 of 45 

Table 4.1.2-2. Availability of uranium air concentration data measured at the twelve Y-12 air 

monitoring stations. 

Year 

Reported 

uranium data Units 

Y-12 monitoring station 

1 2 3 4 5 6 7 8 9 10 11 12 

1983 Total Activity μCi mL-1 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1984 Total Activity μCi mL-1 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1985 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1986 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

19872

 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1988 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1989 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1990 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1991 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1992 Isotopic1 

μCi cm-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

1993 Total Mass μg m-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

19943

 Total Mass μg m-3 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 

19954

 Total Mass μg m-3 ✔ ✔ ✔ 

1996 Total Mass μg m-3 ✔ ✔ ✔ 

1997 Total Mass μg m-3 ✔ ✔ ✔ 

1998 Total Mass μg m-3 ✔ ✔ ✔ 

1999 Total Mass μg m-3 ✔ ✔ ✔ 

1. Concentrations reported for 234U, 235U, 236U and 238U. 

2. Error in reporting units found for 1987 data. See explanation presented with Table 4.1.2-1. 

3. Station 1 inoperable for 1994 and discontinued in 1995. 

4. Sampling at all but three stations discontinued. 

4.2 Approach for Estimating On Site Air Concentrations 

4.2.1 Usability of Air Monitoring Data 

Prior to 1983, the various networks of air monitoring stations in and around the ORR were established 

to monitor for the FP releases. These stations did not measure on site concentrations at Y-12. From 

1959 through 1982, the ambient air monitoring station closest to Y-12 was health physics station HP32 (formerly HP-12), located approximately 0.25 miles from Y-12. In 1983, the first stations dedicated 

to measuring ambient air concentrations at Y-12 were established. 

Ambient air monitoring at Y-12 prior to 1983 is insufficient for estimating environmental doses for 

several reasons: 

•	 Concentrations of airborne uranium within the Y-12 perimeter were measured from 1983 

through 1999. This seventeen-year period represents less than 30% of the operational history 

of the site. In addition, these data were not collected during the time operations and releases 

were at their maximum. Therefore these data cannot be used as estimators of historic air 

concentrations. 

•	 Prior to 1983, the closest health physics station to Y-12 was PAM Station HP-32 (formerly 

known as HP-12). This station was located at Midway Gate, which is north of the intersection 

of Bear Creek Road and Lafayette Drive (approximately 0.25 miles from Y-12). Station 40, 

which replaced station HP-32, began operating in 1983. However, this station is also not 

located on site. 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 14 of 45 

•	 Data from these off site stations consisted of total activity, FP activity, gross α and/or gross β. 

Uranium concentrations were reported as averages across all stations within the PAM 

network. 

•	 No environmental data of any use to this assessment were found for years preceding 1959. 

The only reported on site ambient air concentrations prior to 1959 were for gross α and/or 

gross β. 

•	 An assessment of the measured gross α air concentrations at the health physics stations 

(HP32 and Station 40) show limited correlation to the uranium release quantities estimated for 

the period. 

Given the distance between the main production areas of Y-12 and the locations of these stations 

(HP-32 and Station 40), it is unlikely that these stations reflect the level of on site ambient uranium. 

Consequently, these stations do not present a representative measure of air concentrations at Y-12 

and cannot be used to estimate on site doses. 

The release of contaminants into the atmosphere at Y-12 occurred primarily as a result of plant 

fabrication operations. There are reportedly over 700 permitted air pollution sources that are tied into 

the exhaust ventilation systems of Y-12 (DOE 1989). As reported in the 1988 ASER (DOE 1989), 

approximately 85 exhausts serve areas where depleted uranium (DU) or enriched uranium (EU) were 

processed. As discussed in the Oak Ridge Dose Reconstruction (ORDR) Report (ChemRisk 1999), 

the monitoring of uranium emissions from the various buildings has changed significantly over time. 

Some of these release points were through monitored stacks; others were through vents and exhaust 

systems. 

Estimating airborne concentrations at locations around Y-12 using traditional dispersion and transport 

modeling approaches is confounded by a number of factors: 

•	 Numerous release points which include stacks, vents, and other emission sources, 

•	 The characteristics of the release points, 

•	 The relatively short distances between the release points and the on site receptor locations, 

•	 The complexity of the topography of Y-12, including the presence of Pine Ridge to the north, 

and, 

•	 The density and configuration of buildings at Y-12. 

These factors contribute to the complexity of attempting to model the releases using traditional 

atmospheric dispersion modeling methods. In addition, the approximations necessary to overcome 

these complexities would increase the level of uncertainty in the estimate of doses. 

4.2.2 Empirical Chi/Q (χ/Q) Approach for Estimating Air Concentrations 

Due to the limitations of the available data and the complexity of modeling releases as discussed 

above, an alternative approach was developed for estimating airborne uranium concentrations. An 

empirical relationship was developed using on site measured air concentrations and estimated 

uranium release estimates. This approach circumvents the need for air dispersion modeling by 

providing a direct relationship between uranium air concentrations and uranium releases. In addition, 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 15 of 45 

this approach can be used to estimate air concentrations prior to 1983 by using the empirical Chi/Q 

value and the estimated uranium releases for earlier years. 

Using the available uranium data for 1983 through 1999, the annual average uranium air 

concentration measured at the Y-12 air monitoring stations is divided by the corresponding estimates 

for a given year to estimate an annual, station specific, Chi/Q value. The empirical relationship is 

described by Equation 4.2.2-1 (ChemRisk 1999). 

−3 Uranium AirConcentration (kg m−3 ) Chi Q (m ) =	 Equation 4.2.2-1 

Uranium MassRelease (kg) 

As discussed in the previous section, there were twelve Y-12 air monitoring stations that operated 

from 1984 through 1999. Of these 12 stations, four are located within the Y-12 perimeter; the 

remaining 8 stations are located beyond the fence-line of the facility. These on site locations are Y-12 

air monitoring stations 2, 4, 8 and 12. These stations are located within the boundary of the facility 

and provide coverage of the west (station 8), southeast (station 12), northeast (station 2) and the 

center (station 4) portions of the facility. Annual Chi/Q values were estimated for these four locations. 

4.2.3 Air Concentrations by Location (Chi) 

As shown in Table 4.1.2-2, the Y-12 monitoring stations began operations in 1983; however, the type 

of data reported varied during the 17 years of available information. Uranium air concentrations were 

reported as either total uranium activity, uranium isotope activity or by total uranium mass. Important 

factors associated with the available information include: 

•	 Total uranium activity only was reported for 1983 and 1984. To convert the data for these 

years to isotopic concentrations, the isotopic ratio of the 1985 data for the four uranium 

isotopes (234U, 235U, 236U, and 238U) was used to partition the measured total uranium activity. 

This was necessary in order to calculate a mass-based air concentration that is consistent with 

the other years. 

•	 After 1992, all data were reported in terms of uranium mass (μg m-3). Therefore, data from all 

previous years was converted to a mass basis for consistency. Conversions were achieved 

using specific activities for all four isotopes. 

•	 All stations with the exception of stations 4, 5 and 8 were decommissioned after the 1994 

monitoring period. 

•	 Station 1 was inoperable in 1994, and Station 12 began operations in 1987, four years after 

the other eleven stations were brought on line. 

•	 After 1999, responsibility for the remaining stations (4, 5 and 8) was transferred to TDEC and 

only assessments of gross α and gross β were made from the samples collected. 

All measured air concentrations were converted to kg m-3 of total uranium so that data dimensions are 

consistent for all years. Annual average measured air concentrations for the four Y-12 stations 

selected are tabulated in Tables 4.2.3-1 through 4.2.3-4. Annual average values for gross α, gross β, 

234U, 235U, 236U and 238U are included. All reported concentrations for the uranium isotopes are 

converted to a mass basis (kg m-3) based on specific activities for the four uranium isotopes. For 

1983 and 1984, only the total uranium activity was reported (μCi cm-3). The reported activity was 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 16 of 45 

apportioned to the four uranium isotopes based on the isotopic activity reported for 1985. This 

assumed that the uranium enrichments for 1983 and 1984 were similar to those reported for 1985. 

4.2.4 Release Estimates (Q) 

Release estimates for all buildings at Y-12 were previously estimated by Task 6 of the ORDR Project 

(ChemRisk 1999). These independent estimates were based on a reconstruction of releases from 

stack monitoring data. Estimates of uranium releases were reconstructed for individual exhaust 

stacks and vents and were based on information available for individual buildings, uranium processes 

and from indoor air monitoring data. 

The reconstructed estimates cover the period from 1944 through 1988. Estimates from 1989 through 

1995 were based on reported releases estimated by DOE. For the purposes of this study, release 

estimates after 1995 were derived from the ASERs. 

1944 – 1988 Release estimates were independently reconstructed (ChemRisk 1999). Table 

as part of the ORDR Project. Estimates were D-1 of Appendix D of the 

made of total uranium releases (kg and Ci) and 

isotopic releases (234/235U and 238U). 

Task 6 Report (Volume 5) 

1989-1995 Release estimates reported in the ORDR were not (ChemRisk 1999). Table 

independently reconstructed. Values were based D-1 of Appendix D of the 

on estimates reported by DOE. Task 6 Report (Volume 5) 

1996-2001 Independent sources were not available. Estimates (DOE 2000, DOE 2001, 

are those reported in the ORR – ASER for Y-12. DOE 2002) 

A compilation of these release estimates is presented in Table 4.2.4-1. A combined 234/235U release 

estimate was reconstructed as part of the ORDR Project (ChemRisk 1999). This approach was 

selected by the Dose Reconstruction Team to generate a conservative estimate of off site dose. 

Since these release estimates cannot be distinguished without further reconstruction, the air 

concentrations used in this assessment are in terms of a combined activity (234/235U). Figure 4.2.4-1 

shows the distribution of 234/235U and 238U with time. The highest reconstructed 234/235U release was in 

1958 (17.4 Ci); the highest 238U release was in 1959 (2.0 Ci). 

4.2.5 Correlation of Air Concentrations with Releases 

To validate the Chi/Q approach, the uranium air concentrations measured at each of the four Y-12 

stations of interest (2, 4, 8 and 12) were plotted against the reported uranium release estimates to 

determine if a valid correlation exists. A correlation coefficient (R2

) was estimated from the plotted 

data. Figures 4.2.5-1 through 4.2.5-4 show the relationship of measured air concentrations with 

uranium release estimates. Values of the correlation coefficient (R2

) are included. 

The R2

 values show an acceptable correlation between the measured air concentrations and the 

release estimates indicating that the empirical Chi/Q approach is valid. The only exception is station 

12. The poor correlation is most likely due to the fact that there are only 8 data points for this station. 

This station did not start collecting samples until 1987, which is four years after the other stations 

were brought online. In addition, the range of uranium release estimates for the years when this 

station was operational, is significantly lower than for previous years. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 17 of 45 

0.001 

0.01 

0.1 

1 

10 

100 

1944 1954 1964 1974 1984 1994 

Year 

Y-12 Uranium Release Estimates (Ci) 

Uranium-234/235 Uranium-238 

Figure 4.2.4-1. Distribution of release estimates for the Y-12 facility. Release estimates for 

1944 through 1995 were independently reconstructed by the Oak Ridge Dose Reconstruction 

Project (ChemRisk 1999). 

R2 = 0.95 

0.0E+00 

2.0E-13 

4.0E-13 

6.0E-13 

8.0E-13 

1.0E-12 

1.2E-12 

1.4E-12 

1.6E-12 

1.8E-12 

0 50 100 150 200 250 300 350 

Uranium Release Estimates (kg) 

Total Uranium Air Concentration measured at

Station 2 (kg m-3 ) 

Figure 4.2.5-1. Plot of annual total uranium air concentration measured at Station 2 

verses estimated uranium releases. Correlation coefficient R2

 = 0.95. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 18 of 45 

R2 = 0.70 

0.0E+00 

5.0E-13 

1.0E-12 

1.5E-12 

2.0E-12 

2.5E-12 

3.0E-12 

3.5E-12 

0 50 100 150 200 250 300 350 

Uranium Releases Estimates (kg) 

Total Uranium Air Concentration Measured at

Station 4 (kg m-3 ) 

Figure 4.2.5-2. Plot of annual total uranium air concentration measured at Station 4 

verses estimated uranium releases. Correlation coefficient R2

 = 0.70. 

R2 = 0.87 

0.0E+00 

5.0E-13 

1.0E-12 

1.5E-12 

2.0E-12 

2.5E-12 

3.0E-12 

3.5E-12 

0 50 100 150 200 250 300 350 

Uranium Re le as e Es tim ate s (k g) 

Total Uranium Air Concentration Measured at 

Station 8 (kg m -3) 

Figure 4.2.5-3. Plot of annual total uranium air concentration measured at Station 8 

verses estimated uranium releases. Correlation coefficient R2

 = 0.87. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 19 of 45 

R2 = 0.19 

0.0E+00 

5.0E-14 

1.0E-13 

1.5E-13 

2.0E-13 

2.5E-13 

3.0E-13 

3.5E-13 

4.0E-13 

4.5E-13 

0 20 40 60 80 100 120 140 160 

Uranium Re le as e Es tim ate s (k g) 

Total Uranium Air Concentration Measured at

Station 12 (kg m -3) 

Figure 4.2.5-4. Plot of annual total uranium air concentration measured at Station 12 

verses estimated uranium releases. Correlation coefficient R2

 = 0.19. 

Generally, the correlation of uranium air concentrations with uranium releases displays a strong 

relationship indicating that the stations appropriately represent an adequate measure of ambient 

uranium concentrations as result of uranium releases from Y-12 operations. 

4.2.6 Estimating Chi/Q for Y-12 Stations 

The empirical Chi/Q relationship, described in Equation 4.2.2-1 above, uses the average uranium air 

concentration at each station (Chi) from Tables 4.2.3-1 to 4.2.3-4, and the release estimates (Q) in 

Table 4.2.4-1. Values of Chi/Q are calculated for each of the four locations (Stations 2, 4, 8 and 12) 

by dividing the average annual air concentration estimated in kg m-3 by the release estimates for that 

year in kg. Annual Chi/Q values were calculated for each station for each year for which air 

concentrations were available. 

Station 2 Air concentrations were reported for 1983 through 1994. This 12 Chi/Q values 

station was decommissioned after the 1994 sampling rounds. 

Station 4 Air concentrations were reported for 1983 through 1999. 17 Chi/Q values 

Station 8 Responsibility for this station was transferred to TDEC. Only per station. 

gross α and gross β measurements after 1999. 

Station 12 Air concentrations were reported for 1987 through 1994. This 8 Chi/Q values 

station was added to the network in 1987, and was 

decommissioned after the 1994 sampling rounds. 
Table 4.2.3-1. Annual average air concentrations and estimated Chi/Q values for Y-12 Station 2. 

Year 

Gross α 

(μCi cm-3) 

Gross β 

(μCi cm-3) 

234U 

(μCi cm-3) 

235U 

(μCi cm-3) 

236U 

(μCi cm-3) 

238U 

(μCi cm-3) 

Total Uranium 

(mass or activity) 

19831 - - 3.90E-15 1.61E-16 1.78E-16 2.80E-16 4.52E-15 (μCi cm-3) 

19841 - - 7.08E-15 2.92E-16 3.23E-16 5.08E-16 8.20E-15 (μCi cm-3) 

1985 8.20E-15 2.00E-14 4.60E-15 1.90E-16 2.10E-16 3.30E-16 -1986 6.00E-15 2.80E-14 3.80E-15 1.30E-16 1.00E-16 3.20E-16 -1987 3.32E-15 1.65E-14 1.30E-15 5.00E-17 8.20E-17 1.30E-16 -1988 3.71E-15 2.09E-14 1.55E-15 6.90E-17 8.90E-17 1.81E-16 -1989 2.70E-15 1.90E-14 1.28E-15 7.00E-17 2.60E-17 1.01E-16 -1990 1.31E-15 1.03E-14 4.00E-16 2.49E-17 2.25E-17 5.73E-17 -1991 5.68E-16 6.88E-15 2.00E-16 4.20E-18 2.90E-18 2.14E-17 -1992 1.26E-16 4.52E-15 6.14E-17 4.00E-18 2.40E-18 1.05E-17 -

19932 - - - - - - 6.00E-05 (μg m-3) 

19942 - - - - - - 5.00E-05 (μg m-3) 19952 - - - - - - -

19962 - - - - - - -19972 - - - - - - -19982 - - - - - - -

19992 - - - - - - -

Conversion to 

Mass3 

(kg m-3) 

Y

9.08E-13 1.65E-12 

1.07E-12 1.01E-12 4.10E-13 5.71E-13 3.33E-13 

1.82E-13 

6.55E-14 

3.31E-14 

6.00E-14 5.00E-14 

- 

- 

- 

- 

- 

Station 2 Chi/Q 

Minimum Maximum Count Geometric Mean (GM) Geometric Standard Deviation (G50th Percentile (Lognormal) 

95th Percentile (Lognormal) 

NOTE 1 1983 and 1984 data were reported as total uranium activity only. 234U, 235U, 236U and 238U air concentrations were calculated based on isotopic activ

2 Reported annual average concentration in μg m-3 . 

3 Conversion to mass using specific activities for 234U, 235U, 236U and 238U.
Table 4.2.3-2. Annual average air concentrations and estimated Chi/Q values for Y-12 Station 4. 

Year 

Gross α 

(μCi cm-3) 

Gross β 

(μCi cm-3) 

234U 

(μCi cm-3) 

235U 

(μCi cm-3) 

236U 

(μCi cm-3) 

238U 

(μCi cm-3) 

Total Uranium 

(mass or activity) 

19831 - - 9.61E-15 4.40E-16 2.73E-16 3.69E-16 1.07E-14 (μCi cm-3) 

19841 - - 1.89E-14 8.64E-16 5.36E-16 7.25E-16 2.10E-14 (μCi cm-3) 

1985 2.60E-14 3.20E-14 1.90E-14 8.70E-16 5.40E-16 7.30E-16 -

1986 2.27E-14 5.12E-14 1.57E-14 6.70E-16 7.00E-16 9.60E-16 -

1987 7.25E-15 1.97E-14 4.10E-15 1.80E-16 2.10E-16 3.40E-16 -

1988 5.69E-15 2.25E-14 4.39E-15 1.00E-16 1.15E-16 3.31E-16 -

1989 3.67E-15 2.08E-14 2.40E-15 6.90E-17 4.00E-17 2.69E-16 -

1990 1.88E-15 1.10E-14 1.47E-15 4.83E-17 4.61E-17 8.35E-17 -

1991 6.73E-16 5.64E-15 5.82E-16 1.55E-17 9.00E-18 2.89E-17 -

1992 5.21E-16 4.10E-15 2.23E-16 1.04E-17 3.70E-18 4.69E-17 -

19932 - - - - - - 1.51E-03 (μg m-3) 

19942 - - - - - - 1.20E-04 (μg m-3) 19952 - - - - - - 8.00E-05 (μg m-3) 19962 - - - - - - 9.00E-05 (μg m-3) 19972 - - - - - - 1.50E-04 (μg m-3) 19982 - - - - - - 1.10E-04 (μg m-3) 19992 - - - - - - 8.00E-05 (μg m-3) 

Conversion to 

Mass3 

(kg m-3) 

1.30E-12 

2.56E-12 

2.58E-12 3.17E-12 1.10E-12 1.03E-12 8.31E-13 2.71E-13 9.32E-14 1.44E-13 

1.51E-12 1.20E-13 8.00E-14 9.00E-14 1.50E-13 1.10E-13 8.00E-14 

Station 4 Chi/

Minimum Maximum Count Geometric Mean (GM) Geometric Standard Deviation (50th Percentile (Lognormal) 

95th Percentile (Lognormal) 

NOTE 1 1983 and 1984 data were reported as total uranium activity only. 234U, 235U, 236U and 238U air concentrations were calculated based on isotopic activ

2 Reported annual average concentration in μg m-3 . 

3 Conversion to mass using specific activities for 234U, 235U, 236U and 238U. 
Table 4.2.3-3. Annual average air concentrations and estimated Chi/Q values for Y-12 Station 8. 

Year 

Gross α 

(μCi cm-3) 

Gross β 

(μCi cm-3) 

234U 

(μCi cm-3) 

235U 

(μCi cm-3) 

236U 

(μCi cm-3) 

238U 

(μCi cm-3) 

Total Uranium 

(mass or activity) 

19831 - - 7.20E-15 3.06E-16 2.27E-16 8.19E-16 8.55E-15 (μCi cm-3) 

19841 - - 6.65E-15 2.82E-16 2.10E-16 7.56E-16 7.90E-15 (μCi cm-3) 

1985 1.30E-14 2.20E-14 7.30E-15 3.10E-16 2.30E-16 8.30E-16 -

1986 1.22E-14 3.10E-14 7.20E-15 3.10E-16 1.70E-16 7.50E-16 -

1987 8.30E-15 1.90E-14 6.30E-15 2.90E-16 2.00E-16 3.70E-16 -

1988 4.99E-15 2.46E-14 2.21E-15 1.37E-16 1.68E-16 3.87E-16 -

1989 4.14E-15 2.16E-14 1.68E-15 1.37E-16 6.70E-17 3.23E-16 -

1990 1.69E-15 1.18E-14 4.06E-16 1.99E-17 7.90E-18 1.04E-16 -

1991 5.46E-16 6.51E-15 3.20E-16 5.19E-17 3.60E-18 6.81E-17 -

1992 1.88E-16 4.55E-15 1.90E-16 2.44E-17 5.10E-18 2.46E-17 -

19932 - - - - - - 3.90E-04 (μg m-3) 

19942 - - - - - - 8.00E-05 (μg m-3) 19952 - - - - - - 2.00E-04 (μg m-3) 19962 - - - - - - 9.00E-05 (μg m-3) 19972 - - - - - - 9.05E-05 (μg m-3) 19982 - - - - - - 1.10E-05 (μg m-3) 19992 - - - - - - 8.00E-05 (μg m-3) 

Conversion to 

Mass3 

(kg m-3) 

Y

2.58E-12 2.38E-12 

2.61E-12 2.37E-12 1.24E-12 1.21E-12 1.02E-12 3.18E-13 2.26E-13 8.44E-14 

3.90E-13 8.00E-14 2.00E-13 9.00E-14 9.05E-14 1.10E-14 8.00E-14 

Station 8 Chi/

Minimum Maximum Count Geometric Mean (GM) Geometric Standard Deviation 50th Percentile (Lognormal) 

95th Percentile (Lognormal) 

NOTE 

1 1983 and 1984 data were reported as total uranium activity only. 234U, 235U, 236U and 238U air concentrations were calculated based on isotopic 

2 Reported annual average concentration in μg m-3 . 

3 Conversion to mass using specific activities for 234U, 235U, 236U and 238U. 
Table 4.2.3-4. Annual average air concentrations and estimated Chi/Q values for Y-12 Station 12. 

Year 

Gross α 

(μCi cm-3) 

Gross β 

(μCi cm-3) 

234U 

(μCi cm-3) 

235U 

(μCi cm-3) 

236U 

(μCi cm-3) 

238U 

(μCi cm-3) 

Total Uranium 

(mass or activity) 

19831 - - - - - - -

19841 - - - - - - -19851 - - - - - - -

19861 - - - - - - -

1987 2.78E-15 1.21E-14 5.20E-16 6.10E-17 7.00E-17 5.70E-17 -

1988 4.06E-15 2.31E-14 1.01E-15 7.40E-17 7.20E-17 1.27E-16 -

1989 3.10E-15 2.08E-14 1.32E-15 8.80E-17 6.90E-17 1.15E-16 -

1990 1.61E-15 1.23E-14 3.21E-16 1.48E-17 8.90E-18 5.35E-17 -

1991 4.93E-16 6.84E-15 1.34E-16 3.46E-17 9.30E-18 2.79E-17 -

1992 2.14E-16 5.41E-15 5.62E-17 2.50E-18 1.50E-18 8.10E-18 -

19932 - - - - - - 6.00E-05 (μg m-3) 

19942 - - - - - - 5.00E-05 (μg m-3) 19952 - - - - - - -

19962 - - - - - - -19972 - - - - - - -19982 - - - - - - -

19992 - - - - - - -

Conversion to 

Mass3 

(kg m-3) 

- 

- 

- 

- 

1.99E-13 4.12E-13 3.83E-13 1.66E-13 9.90E-14 2.52E-14 

6.00E-14 5.00E-14 

- 

- 

- 

- 

- 

Station 12 Ch

Minimum Maximum Count Geometric Mean (GM) Geometric Standard Deviation 50th Percentile (Lognormal) 

95th Percentile (Lognormal) 

NOTE 1 Station was not operational and was brought on line in 1987 2 Reported annual average concentration in μg m-3 . 

3 Conversion to mass using specific activities for 234U, 235U, 236U and 238U. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 24 of 45 

Table 4.2.4-1. Compiled annual uranium release estimates (Q). 

Year 

Uranium 

(kg) 

Uranium 

(Ci) 

234/235U 

(kg) 

238U 

(kg) 

234/235U 

(Ci) 

238U 

(Ci) Source 

1944 311 0.35 5 307 0.24 0.11 ChemRisk 1999 (Table D-1) 

1945 665 0.63 8 657 0.41 0.22 ChemRisk 1999 (Table D-1) 

1946 385 0.44 6 379 0.31 0.13 ChemRisk 1999 (Table D-1) 

1947 250 0.34 5 245 0.26 0.08 ChemRisk 1999 (Table D-1) 

1948 650 0.39 3 647 0.17 0.22 ChemRisk 1999 (Table D-1) 

1949 650 0.39 3 647 0.17 0.22 ChemRisk 1999 (Table D-1) 

1950 650 0.39 3 647 0.17 0.22 ChemRisk 1999 (Table D-1) 

1951 650 0.39 3 647 0.17 0.22 ChemRisk 1999 (Table D-1) 

1952 650 0.39 3 647 0.17 0.22 ChemRisk 1999 (Table D-1) 

1953 4015 2.04 12 4002 0.67 1.36 ChemRisk 1999 (Table D-1) 

1954 3765 1.86 11 3754 0.58 1.28 ChemRisk 1999 (Table D-1) 

1955 3765 1.87 11 3754 0.59 1.28 ChemRisk 1999 (Table D-1) 

1956 3037 4.2 41 2995 3.2 1 ChemRisk 1999 (Table D-1) 

1957 2309 6.6 72 2236 5.8 0.8 ChemRisk 1999 (Table D-1) 

1958 5657 19.2 214 5443 17.4 1.8 ChemRisk 1999 (Table D-1) 

1959 6149 13.9 148 6001 11.9 2 ChemRisk 1999 (Table D-1) 

1960 934 2.73 28 906 2.43 0.31 ChemRisk 1999 (Table D-1) 

1961 1321 4.33 45 1276 3.9 0.43 ChemRisk 1999 (Table D-1) 

1962 1390 4.67 49 1341 4.21 0.46 ChemRisk 1999 (Table D-1) 

1963 2091 2.83 28 2063 2.1 0.7 ChemRisk 1999 (Table D-1) 

1964 2672 1.58 10 2662 0.68 0.91 ChemRisk 1999 (Table D-1) 

1965 635 3.61 42 593 3.41 0.2 ChemRisk 1999 (Table D-1) 

1966 921 1.4 14 907 1.09 0.31 ChemRisk 1999 (Table D-1) 

1967 339 0.62 6 332 0.5 0.11 ChemRisk 1999 (Table D-1) 

1968 439 0.37 3 436 0.22 0.15 ChemRisk 1999 (Table D-1) 

1969 247 1.05 12 235 0.97 0.08 ChemRisk 1999 (Table D-1) 

1970 295 1.68 19 276 1.59 0.09 ChemRisk 1999 (Table D-1) 

1971 575 2.26 25 549 2.07 0.19 ChemRisk 1999 (Table D-1) 

1972 874 3.95 47 827 3.66 0.28 ChemRisk 1999 (Table D-1) 

1973 410 3.36 39 371 3.23 0.13 ChemRisk 1999 (Table D-1) 

1974 208 0.35 4 204 0.28 0.07 ChemRisk 1999 (Table D-1) 

1975 210 0.59 7 203 0.52 0.07 ChemRisk 1999 (Table D-1) 

1976 208 0.4 4 204 0.33 0.07 ChemRisk 1999 (Table D-1) 

1977 206 0.23 2 204 0.16 0.07 ChemRisk 1999 (Table D-1) 

1978 206 0.24 2 204 0.17 0.07 ChemRisk 1999 (Table D-1) 

1979 207 0.31 3 204 0.24 0.07 ChemRisk 1999 (Table D-1) 

1980 222 0.54 6 216 0.47 0.07 ChemRisk 1999 (Table D-1) 

1981 207 0.36 4 203 0.29 0.07 ChemRisk 1999 (Table D-1) 

1982 207 0.55 6 201 0.48 0.07 ChemRisk 1999 (Table D-1) 

1983 208 0.48 5 203 0.41 0.07 ChemRisk 1999 (Table D-1) 

1984 331 0.46 5 326 0.35 0.11 ChemRisk 1999 (Table D-1) 

1985 211 0.35 4 207 0.28 0.07 ChemRisk 1999 (Table D-1) 

1986 213 0.42 5 208 0.35 0.07 ChemRisk 1999 (Table D-1) 

1987 153 0.64 7 146 0.59 0.05 ChemRisk 1999 (Table D-1) 

1988 145 0.35 4 142 0.3 0.05 ChemRisk 1999 (Table D-1) 

1989 44 0.15 7 37 0.15 0.014 ChemRisk 1999 (Table D-1) 

1990 21 0.8 6 15 0.08 0.007 ChemRisk 1999 (Table D-1) 

1991 21 0.05 1 20 0.04 0.01 ChemRisk 1999 (Table D-1) 

1992 7 0.04 1 7 0.04 0.006 ChemRisk 1999 (Table D-1) 

1993 3 0.03 0.4 3 0.03 0.003 ChemRisk 1999 (Table D-1) 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 25 of 45 

Table 4.2.4-1. (Continued) 

Year 

Uranium 

(kg) 

Uranium 

(Ci) 

234/235U 

(kg) 

238U 

(kg) 

234/235U 

(Ci) 

238U 

(Ci) Source 

1994 24 0.04 0.4 24 0.03 0.002 ChemRisk 1999 (Table D-1) 

1995 2 0.02 0.3 2 0.02 0.0021 ChemRisk 1999 (Table D-1) 

1996 9.7 - - - - - DOE 2000, page 6-2 

1997 6 - - - - - DOE 2000, page 6-2 

1998 10 - - - - - DOE 2000, page 6-2 

1999 3.9 - - - - - DOE 2000, page 6-2 

2000 2.2 - - - - - DOE 2001, page 6-5 

2001 3.4 - - - - DOE 2002, page 6-5 

Given the limited number of data points, a definitive characterization of the underlying distribution was 

not possible with any statistical certainty. However, the distribution of Chi/Q values exhibit 

characteristics of a lognormal distribution with a defined tail of higher values. Estimations of central 

tendency were made assuming the distribution of the Chi/Q values for each station was lognormal 

and estimates of the geometric mean (GM) and geometric standard deviation (GSD) are included in 

Tables 4.2.3-1 to 4.2.3-4. Estimates of the 50th and 95th percentile value of the Chi/Q value for each 

station were generated assuming the underlying distributions were lognormal. The percentiles were 

calculated using Equation 4.2.6-1, as described by Gilbert (1987). 

xˆ 

p = exp( y + Z p s y ) Equation 4.2.6-1 

Where: 

xˆ p = pth percentile of data set assuming distribution is lognormal, 

y = arithmetic mean of the log transformed values of Chi/Q, 

Zp = pth percentile of a standard normal distribution, 

sy = standard deviation of the log transformed values of Chi/Q. 

4.3 Estimation of Air Concentrations 

Uranium air concentrations and annual intakes were calculated for the four on site locations at Y-12. 

These locations are represented by Y-12 air monitoring stations 2, 4, 8 and 12. These stations are 

located within the boundary of the facility and provide coverage of the west (station 8), southeast 

(station 12), northeast (station 2) and the center (station 4) portions of the facility (Figure 4.3-1). 

Utilizing the Chi/Q estimates for each station, and the annual Y-12 airborne release estimates in Table 

4.2.4-1, annual uranium air concentrations (Ci m-3) at the four locations were obtained by multiplying 

the Chi/Q value for each station (m-3) by the uranium release estimate (Ci) for 234/235U and 238U. 

Annual uranium air concentration was calculated for each of the four specified locations for all years 

from 1944 to 2002. The air concentrations were estimated using the 50th and 95th percentile values 

for the Chi/Q values for each station. Even though measured uranium concentrations in air were 

available for 1983 through 1999, the air concentrations generated by the Chi/Q approach were used 

to estimate intakes. This approach was selected to maintain consistency with the preceding years. 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 26 of 45 

Figure 4.3-1. Locations of Y-12 perimeter air monitoring stations (DOE 1990). 

The ORDR Project estimated releases from 1944 to 1995. Thus, this source cannot be used to 

estimate air concentrations from 1996 to 2002. The release estimates in Table 4.2.4-1 show a 

definite downward trend for the years preceding 1995 (Figure 4.3-2). Thus, it is conservative to 

assume that the air concentrations reported from 1996 to 2002 are equal to the concentrations 

reported for 1995. 

0.001 

0.01 

0.1 

1 

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 

Year 

Uranium Releases (Ci) 

Uranium-234/235 Uranium-238 

Figure 4.3-2. Distribution of 234/235U and 238U release estimates for the years 1985 through 

1995. The trend shows a definite downward trend for the years preceding 1995. 
 

 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 27 of 45 

Air concentrations and intakes for the four on site locations are presented in Tables D-1 to D-4 in 

Attachment D. The uranium air concentrations are based on the 50th and 95th percentile value of the 

lognormally distributed Chi/Q. 

In addition, a site wide average air concentration and intake were estimated based on the annual 

concentrations from stations 2, 4, 8 and 12. These values are reported in Table D-5 in Attachment D. 

The maximum air concentrations for the uranium isotopes from all four locations were also compiled. 

The 50th and 95th percentiles of both air concentration and intake are presented in Table D-6 in 

Attachment D. Note that the percentiles are based on the statistics of the Chi/Q estimation and not on 

the data from the four stations. 

Estimates of intake assume 2,000 h y-1 exposure. An inhalation rate of 1.2 m3

 h-1 generates an 

annual intake off 2,400 m3

 y-1 . 

For estimating air concentrations and intakes for
 

the four specific on site locations at Y-12 by Tables D-1 through D-4 

selecting the location that closely represents Average and the exposure location. 95th Percentile air For estimating Y-12 average air concentrations concentration and and intakes based on an annual average from Table D-5 intake for all four on site locations.	 234/235U and 238U Maximum air concentrations and intakes based 

on the highest Chi/Q value (represented by Table D-6 

Station 4) 

4.4 Occupational External Dose 

There are two potential sources of external exposures received by workers at the Y-12 facility: 

1. Exposures from the deposition of radionuclides released as a consequence of facility 

operations, 

2. Exposures received from radiation levels emanating from buildings and storage areas. 

4.4.1 Data Availability 

Environmental monitoring of external exposures was performed at health physics monitoring stations 

and is reported in the Annual Site Environmental Reports. Prior to 1983, the only health physics 

monitoring stations for Y-12 were located off site, and consequently were not useful for estimating 

worker exposures. No measurements of external exposures were reported for the twelve on site 

stations at Y-12, which began operations in 1983. With the exception of the limited data from 

environmental monitoring reports, there are two major characterizations of external exposures that 

have been performed for Y-12. A series of aerial radiological surveys was performed in 1973-1974, 

1980, 1989 and 1992 for the ORR that included Y-12. These surveys consisted of a reservation wide, 

high level survey and low-level facility specific surveys. The second major characterization was 

performed from 1985 to 1987 and involved an outdoor radiological and chemical scoping survey of the 

800+ acres occupied by the Y-12 facility. This survey included both radiological and chemical 

assessments and included measurements of both gamma ray exposure rates and the collection of 
 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 28 of 45 

surface soil samples. The purpose of the scoping survey was to locate and prioritize areas of concern 

from both a worker health and safety and from an environmental assessment standpoint. The 

approach, results and relative merits of both efforts are discussed below. 

4.4.2 Range of Exposures from Aerial Surveys 

Aerial Radiological Survey 1973-1974 (EG&G 1976) 

The survey consisted of airborne measurements of both man-made and natural radioisotopes in and 

around the three DOE facilities as well as surrounding areas that are not part of the ORR. Results 

were presented as radiation intensity isopleths that were superimposed onto aerial photographs. 

Aerial measurements were related to exposure levels at one meter above ground. The natural 

background levels were estimated to vary between 4 to 6 μR h-1 for Y-12. This does not include an 

exposure rate of 3.8 μR h-1 from cosmic radiation. 

Radiation levels at Y-12 can be separated into five distinct areas of higher than background 

exposures. The highest exposure range of 50-100 μR h-1 was centered around a waste disposal 

pond located at the west end of the facility. Higher areas were inferred from the 208Tl peak 

(attributable to thorium). These exposures were attributed to a coal pile. Additional 208Tl isopleths 

were attributed to thorium storage areas producing maximum exposure values ranging from 13 to 25 

μR h-1. Tons of 238U stored at the west end of Y-12 produced maximum levels ranging from 50 to 100 

μR h-1 . Exposure rates in these five areas range from 1.5 to 100 μR h-1 over approximately 50% of 

the site. 

Other sources included collimated sources and x-ray machines located in buildings. Multiple flyovers 

indicate that these sources were not in constant operation. 

Aerial Radiological Survey 1980 (EG&G 1984) 

The focus of the second aerial survey was to identify specific radiological sources including 60Co,

234mPa and 137Cs. Isopleths for the vicinity of the Y-12 area show three major areas of elevated 

exposure rates. All are located towards the west end of the facility with the highest isopleths relating 

to an exposure rate of 100 to 200 μR h-1 . The resolution of the isopleths prevents a determination of 

exact location of these sources of higher exposure. These areas of higher exposure are limited to the 

west side of the facility. The remainder of Y-12 is within the 11.8 to 20 μR h-1 exposure range. 

 Aerial Radiological Survey 1989 (EG&G 1992) 

The exposure rates for the Y-12 facility show a reduction in the number of areas of elevated readings 

as compared to the 1980 survey. The highest exposures are still localized over a small area at the 

west end of the site. The net spectra are dominated by the 234mPa photopeak indicating the presence 

of DU. Maximum exposures ranged from 35 to 80 μR hr-1 for this area. Two smaller areas in the 14 

to 35 μR h-1 range were noted in the center portion of the site. The spectra for one of these areas are 

related to the 235U and appear to be centered over the production areas. This photopeak was not 

observed during the previous flyover. The net spectra for the other area are indicative of Th. 

Aerial Radiological Survey 1992 (EG&G 1993) 

The 1992 survey identified six areas within the Y-12 complex with elevated exposure rates. Three of 

these areas show evidence of 234mPa, indicating that the source is DU. The highest area is located 

toward the west end of the site with the maximum isopleth range of 20 to 50 μR h-1 . This area of 

concern, attributed to DU, is likely to be the same source area (waste disposal area) as identified in 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 29 of 45 

previous surveys. The maximum isopleths for the other 5 areas range from 13 to 20 μR h-1 . The 

spectra for two of these areas show the characteristic photopeak for 235U and are located over areas 

that are either associated with production or material storage. The remainder of the site is 

encompassed by isopleths ranging from 8 to 13 μR h-1 . 

4.4.3 Results of 1987 Scoping Survey 

An outdoor radiological and chemical scoping survey was conducted at Y-12 between September 

1985 and May 1987 (Foley and Carrier 1990). The survey included the approximately 800 acres of 

the plant, as well as adjacent areas where emission depositions likely occurred. The purpose of the 

survey was to locate and prioritize areas of concern from both a worker health and safety and from an 

environmental assessment standpoint. The survey included measurements of both gamma ray 

exposure rates and collection of surface soil samples. The measurement of gamma ray exposure 

rates was made by direct measurements at grid locations and by scans of areas within grid blocks. 

The entire site was initially partitioned into 22 priority areas. Five areas were later sub-divided to form 

additional survey areas for a total of 27 priority areas. The priority areas were established by Y-12 

Management to encompass logical units of operation and to maintain manageable survey grids. Each 

area was further divided into grid blocks according to the Y-12 master grid plan. Each block varied in 

size according to the degree of contamination expected. Grid blocks with closely spaced buildings 

were sized as 100’x100’; open areas were divided into 200’x200’ grid blocks. 

Exposure measurements for each grid block comprised of a range of exposure levels and direct 

readings at specific grid intersections. Each grid block was thoroughly scanned with a portable 

gamma scintillation meter (11⁄4” x 11⁄2” NaI probe). The scan produced a range of exposure levels for 

each grid block. Direct exposure measurements were also made at each grid line intersection. All 

gamma measurements were made at ground surface. 

The results of the scans and direct measurements were tabulated for each of the 27 priority areas. 

Ranges of measurements were provided in the report, but no further analysis of the data was 

performed. To generate a site wide estimate for gamma ray exposure, values were assembled for 

each of the 1787 grid blocks. Values for each grid block were presented as direct measurements 

taken at each grid point and as a range of exposures measured during the scan. 

4.4.4 Estimated External Exposures for Y-12 Workers 

The four aerial surveys discussed above present reasonable ranges of elevated external exposures. 

However, the purpose of these surveys was to identify specific sources of higher than background 

radiation levels. The focus of the latter aerial surveys was to isolate and identify sources such as 

waste pits and storage areas. The resulting isopleths from these surveys have relatively poor 

resolution and are not reliable for estimating a site wide average exposure rate. Some of the major 

sources identified by the aerial surveys were attributed to collimated sources that were not in constant 

operation. In addition, the isopleths generated by these surveys are dominated by the high radiation 

source areas and provide little or no definition for localized areas. Interpreting a site wide average 

was not possible from these aerial surveys. 

Because of the limitations of the aerial surveys, it was decided to use the results of the 1987 outdoor 

scoping survey for estimating external exposures. The scoping survey is a comprehensive 

assessment of radiation exposures and encompasses all areas of the site. There are 1787 grids and 

the resolution of the grids (100 feet x100 feet to 200 feet x 200feet) ensures that all localized hotspots are included. The purpose of the scoping survey was to locate and prioritize areas of concern 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 30 of 45 

from both a worker health and safety and from an environmental assessment standpoint and is 

therefore most relevant to assessing worker exposure. 

For this Technical Basis Document, the highest exposure reading from either the scan or the direct 

measurement presented in the scoping survey was used. This approach presented the most 

conservative method of estimating exposures and ensures that areas of high exposure levels within 

each grid were included in the site wide average. It was noted that numerous grid blocks exhibited 

high exposure readings, but these areas were not subjected to direct measurements. Higher readings 

were attributed to either shine from nearby buildings and storage areas or to localized hot-spots. 

By utilizing the highest direct exposure value from either the scans or the direct readings, exposures 

attributable to shine or localized hot-spots were included in the assessment. Since the purpose of this 

assessment is to estimate doses received from ambient external radiation, neglecting these areas of 

high exposure would not encompass external exposures potentially received by people working in 

these areas. 

Natural terrestrial background at Y-12 was inferred by the aerial survey conducted in 1973-1974 

(EG&G 1976). The exposure rate (at 1 m above ground) ranged from 4 to 6 μR h-1, excluding cosmic 

radiation. An exposure rate of 3.8 μR h-1 was estimated as the exposure rate from cosmic radiation. 

The aerial estimates were made at one meter above ground and the results from the scoping survey 

were measured at ground surface. Thus, an estimated natural background rate (8 μR h-1) was 

calculated by summing the lowest value of the background exposure rate range from the aerial survey 

and the cosmic radiation component. 

The 1787 exposure measurements used for this analysis ranged from 4 to 1,500 μR h-1 . However 

88% of the data was less than 100 μR h-1 indicating a definitive skew to the data, and this was 

confirmed with plots of all data. Therefore, a lognormal distribution was used for the range of 

exposure rates presented in the scoping survey. The data are presented below. 

Minimum 

Measured 

exposure rate 

(μR h-1) 

4 

Measured exposure rate 

excluding background 

(μR h-1) 

0 

Maximum 1500 1492 

Geometric Mean (GM) 

Geometric Standard Deviation (GSD) 

50th Percentile 

21 

3.0 

21 

13 

13 

95th Percentile 129 121 

The highest exposure readings were generally attributed to the shine emanating from nearby 

buildings, storage areas or waste pits. Although these readings are not indicative of the level of 

radioactivity in soils and surfaces, contributions from shine are valid sources of exposure for workers. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 31 of 45 

REFERENCES 

Abee 1960a. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for 1959. H.H. 

Abee, Oak Ridge National Laboratory, May 1960. 60-5-138. 

ChemRisk Doc 1884. 

Abee 1960b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for the First 

Quarter, 1960. H.H. Abee, Oak Ridge National Laboratory, May 1960. 60-5-139. 

ChemRisk Doc 1878 

Abee 1961. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for the Fourth 

Quarter, 1960. H.H. Abee, Oak Ridge National Laboratory, March 1961. TID-13849. 

ChemRisk Doc 3182 

ChemRisk 1999. Uranium Releases from the Oak Ridge Reservation – A Review of the Quality of 

Historical Effluent Monitoring Data and a Screening Evaluation of Potential Exposures. 

Reports of the Oak Ridge Dose Reconstruction, Volume 5. The Report of the Project Task 6, 

1999. 

DOE 1987a. Environmental Surveillance of the U.S. Department of Energy Oak Ridge Reservation 

and Surrounding Environs During 1986 – Volume 1. U.S. Department of Energy, April 1987. 

ES/ESH-1/V1. 

ChemRisk Doc 369 

DOE 1987b. Environmental Surveillance of the U.S. Department of Energy Oak Ridge Reservation 

and Surrounding Environs During 1986 – Volume 2. U.S. Department of Energy, April 1987. 

ES/ESH-1/V2. 

ChemRisk Doc 369 

DOE 1988a. Environmental Surveillance of the U.S. Department of Energy Oak Ridge Reservation 

and Surrounding Environs During 1987 – Volume 1. U.S. Department of Energy, April 1988. 

ES/ESH-4/V1. 

ChemRisk Doc 370 

DOE 1988b. Environmental Surveillance of the U.S. Department of Energy Oak Ridge Reservation 

and Surrounding Environs During 1987 – Volume 2. U.S. Department of Energy, April 1988. 

ES/ESH-4/V2. 

ChemRisk Doc 371 

DOE 1989. Oak Ridge Reservation Environmental Report for 1988 – Volume 1. U.S. Department of 

Energy, May 1989. ES/ESH-8/V1. 

ChemRisk Doc 254 

DOE 1990. Oak Ridge Reservation Environmental Report for 1989 – Volume 1. U.S. Department of 

Energy, October 1991. ES/ESH-13/V1. 

ChemRisk Doc 226 

DOE 1991. Oak Ridge Reservation Environmental Report for 1990 – Volume 1. U.S. Department of 

Energy, September 1991. ES/ESH-18/V1. 

ORAU Library 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 32 of 45 

DOE 1992a. Oak Ridge Reservation Environmental Report for 1991 – Volume 1. U.S. Department of 

Energy, October 1992. ES/ESH-22/V1. 

ChemRisk Doc 709 

DOE 1992b. Oak Ridge Reservation Environmental Report for 1992 – Volume 2. U.S. Department of 

Energy, September 1993. ES/ESH-22/V2. 

ChemRisk Doc 709 

DOE 1993a. Oak Ridge Reservation Environmental Report for 1992 – Volume 1. U.S. Department of 

Energy, September 1993. ES/ESH-31/V1. 

ChemRisk Doc 3281 

DOE 1993b. Oak Ridge Reservation Environmental Report for 1992 – Volume 2. U.S. Department of 

Energy, September 1993. ES/ESH-31/V2. 

ChemRisk Doc 3281 

DOE 1994. Oak Ridge Reservation Annual Site Environmental Report for 1993 – Volume 1. U.S. 

Department of Energy, November 1994. ES/ESH-47 

ChemRisk Doc 3281 

DOE 1995. Oak Ridge Reservation Annual Site Environmental Report for 1994. U.S. Department of 

Energy, October 1995. ES/ESH-57/V1. 

ChemRisk Doc 3281 

DOE 1996. Oak Ridge Reservation Annual Site Environmental Report for 1995. U.S. Department of 

Energy, September 1996. ES/ESH-69 

http://www.ornl.gov.aser 

DOE 1997. Oak Ridge Reservation Annual Site Environmental Report for 1996. U.S. Department of 

Energy, October 1997. ES/ESH-73 

http://www.ornl.gov.aser 

DOE 1998. Oak Ridge Reservation Annual Site Environmental Report for 1997. U.S. Department of 

Energy, October 1998. ES/ESH-78 

http://www.ornl.gov.aser 

DOE 1999. Oak Ridge Reservation Annual Site Environmental Report for 1998. U.S. Department of 

Energy, December 1999. DOE/ORO/2091 

http://www.ornl.gov.aser 

DOE 2000. Oak Ridge Reservation Annual Site Environmental Report for 1999. U.S. Department of 

Energy, September 2000. DOE/ORO/2100 

http://www.ornl.gov.aser 

DOE 2001. Oak Ridge Reservation Annual Site Environmental Report for 2000. U.S. Department of 

Energy, September 2001. DOE/ORO/2119 

http://www.ornl.gov.aser 

DOE 2002. Oak Ridge Reservation Annual Site Environmental Report for 2001. U.S. Department of 

Energy, September 2002. DOE/ORO/2133 

http://www.ornl.gov.aser 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 33 of 45 

EG&G 1976. Aerial Radiological Surveys of the ERDA’s Oak Ridge Facilities and Vicinity (Survey 

Period: 1973-1974). EGG-1183-1682, February 1976. 

ChemRisk Doc 118 

EG&G 1984. An Aerial Radiological Survey of the Oak Ridge Reservation (Date of Survey: June 

1980). EGG-10282-1001. January 1984. 

ChemRisk Doc 606 

EG&G 1992. An Aerial Radiological Survey of the Oak Ridge Reservation and Surrounding Area 

(Date of Survey: September 1989). EGG-10617-1123, April 1992. 

ChemRisk Doc 1189 

EG&G 1993. An Aerial Radiological Survey of the Oak Ridge Reservation (Date of Survey: April 

1992). EGG-10617-1229. April 1993. 

Foley, R.D., and R.F. Carrier 1990. The Outdoor Radiological and Chemical Surface Scoping Survey 

of the Y-12 Plant Site: Part 2 – The 1985-1987 Data Base. Prepared by the Health and 

Safety Research Division, Oak Ridge National Laboratory. Final Report Issued March 1990. 

Y/TS-600 PART 2. 

Gilbert 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand Reinhold 

Publishers, 1987. 

MMES 1984. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1983. Martin Marietta Energy Systems, Inc., June 1984. Y/UB-19. 

MMES 1985. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1984. Martin Marietta Energy Systems, Inc., August 1985. ORNL6209. 

MMES 1986. Environmental Surveillance of the Energy Oak Ridge Reservation and Surrounding 

Environs During 1985. Martin Marietta Energy Systems, Inc., April 1986. ORNL-6271. 

ChemRisk Doc 199 

ORNL 1961. Applied Health Physics Annual Report for 1960. Health Physics Division, Oak Ridge 

National Laboratory. July 1961. ORNL-3159 

ChemRisk Doc 542 

ORNL 1962. Applied Health Physics Annual Report for 1961. Oak Ridge National Laboratory. 

November 1962. ORNL-3284 

ChemRisk Doc 543 

ORNL 1963. Applied Health Physics Annual Report for 1962. Oak Ridge National Laboratory. 

September 1963. ORNL-3490 

ChemRisk Doc 544 

ORNL 1964a. Applied Health Physics Annual Report for 1963. Oak Ridge National Laboratory. 

August 1964. ORNL-3665 

ChemRisk Doc 545 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 34 of 45 

ORNL 1964b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1963. Applied Health Physics Section, Oak Ridge National Laboratory. 800830 

ChemRisk Doc 502 

ORNL 1965a. Applied Health Physics Annual Report for 1964. Oak Ridge National Laboratory. June 

1965. ORNL-3820 

ChemRisk Doc 546 

ORNL 1965b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1964. Applied Health Physics and Safety Section, Oak Ridge National Laboratory. 

800829 

ChemRisk Doc 501 

ORNL 1966a. Health Physics and Safety Annual Report for 1965. Oak Ridge National Laboratory. 

July 1966. ORNL-3969 

ChemRisk Doc 547 

ORNL 1966b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period 

January – June, 1965. Applied Health Physics and Safety Section, Oak Ridge National 

Laboratory. 800828 

ChemRisk Doc 500 

ORNL 1966c. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1965. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1967a. Health Physics and Safety Annual Report for 1966. Oak Ridge National Laboratory. 

August 1967. ORNL-4146 

ChemRisk Doc 548 

ORNL 1967b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period 

January – June, 1966. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1967c. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1966. Health Physics and Safety Section, Oak Ridge National Laboratory. 

800827 

ChemRisk Doc 499 

ORNL 1968a. Health Physics and Safety Annual Report for 1967. Oak Ridge National Laboratory. 

August 1968. ORNL-4286 

ChemRisk Doc 549 

ORNL 1968b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period 

January – June, 1967. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1968c. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1967. Health Physics and Safety Section, Oak Ridge National Laboratory. 

800826 

ChemRisk Doc 497 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 35 of 45 

ORNL 1969a. Applied Health Physics and Safety Annual Report for 1968. Oak Ridge National 

Laboratory. July 1969. ORNL-4423 

ChemRisk Doc 550 

ORNL 1969b. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period 

January – June, 1968. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1969c. Environmental Levels of Radioactivity for the Oak Ridge Area. Report for Period July – 

December, 1968. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1969d. Environmental Levels of Radioactivity for the Oak Ridge Area. Report Period January 

– June, 1969. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1969e. Environmental Levels of Radioactivity for the Oak Ridge Area. Report Period July – 

December, 1969. Health Physics and Safety Section, Oak Ridge National Laboratory. 

ChemRisk Doc 1454 

ORNL 1970. Applied Health Physics and Safety Annual Report for 1969. Oak Ridge National 

Laboratory. August 1970. ORNL-4563 

ChemRisk Doc 551 

ORNL 1971. Applied Health Physics and Safety Annual Report for 1970. Oak Ridge National 

Laboratory. August 1971. ORNL-4690. 

Chemrisk Doc 552 

UCC 1972. Environmental Monitoring Report, United States Atomic Energy Commission, Oak Ridge 

Facilities, Calendar Year 1971 Union Carbide Corporation – Nuclear Division, June1972. 

UCC-ND-221. 

UCC 1973. Environmental Monitoring Report, United States Atomic Energy Commission, Oak Ridge 

Facilities, Calendar Year 1972. Union Carbide Corporation – Nuclear Division, March 1973. 

UCC-ND-244. 

UCC 1974. Environmental Monitoring Report, United States Atomic Energy Commission, Oak Ridge 

Facilities, Calendar Year 1973. Union Carbide Corporation – Nuclear Division, May 1974. 

UCC-ND-280. 

UCC 1975. Environmental Monitoring Report, United States Energy Research and Development 

Administration, Oak Ridge Facilities, Calendar Year 1974. Union Carbide Corporation – 

Nuclear Division, May 1975. UCC-ND-302. 

UCC 1976. Environmental Monitoring Report, United States Energy Research and Development 

Administration, Oak Ridge Facilities, Calendar Year 1975. Union Carbide Corporation – 

Nuclear Division, May 1976. Y/UB-4. 

UCC 1977. Environmental Monitoring Report, United States Energy Research and Development 

Administration, Oak Ridge Facilities, Calendar Year 1976. Union Carbide Corporation – 

Nuclear Division, May 1977. Y/UB-6. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 36 of 45 

UCC 1978. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1977. Union Carbide Corporation – Nuclear Division, June 1978. 

Y/UB-8. 

UCC 1979. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1978. Union Carbide Corporation – Nuclear Division, June 1979. 

Y/UB-10. 

UCC 1980. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1979. Union Carbide Corporation – Nuclear Division, June 1980. 

Y/UB-13. 

UCC 1981. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1980. Union Carbide Corporation – Nuclear Division, June 1981. 

Y/UB-15. 

UCC 1982. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1981. Union Carbide Corporation – Nuclear Division, May 1982. 

Y/UB-16. 

UCC 1983. Environmental Monitoring Report, United States Department of Energy Oak Ridge 

Facilities, Calendar Year 1982. Union Carbide Corporation – Nuclear Division, May 1983. 

Y/UB-18. 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 37 of 45 

GLOSSARY 

BEING PREPARED 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 38 of 45 

ATTACHMENT D 

OCCUPATIONAL ENVIRONMENTAL DOSE 

LIST OF TABLES 

D-1 Calculated 234/235U and 238U air concentrations and intakes for Station 2............................39 

D-2 Calculated 234/235U and 238U air concentrations and intakes for Station 4............................40 

D-3 Calculated 234/235U and 238U air concentrations and intakes for Station 8............................41 

D-4 Calculated 234/235U and 238U air concentrations and intakes for Station 12..........................42 

D-5 Site wide 234/235U and 238U air concentrations and Intakes based on 

average air concentrations for Stations 2, 4, 8 and 12........................................................43 

D-6 Maximum 234/235U and 238U air concentrations and intakes .................................................44 

D-7 Ambient external dose rates outside building on Y-12 site....................................... 44 

D.1 Occupational Environmental Dose for Unmonitored Workers 

The occupational environmental dose received by unmonitored workers is limited to exposures 

received while outside buildings and within the perimeter of the Y-12 Plant. Buildings and other 

operational units occupy the vast majority of the land area at Y-12. This assessment will quantify 

exposure for unmonitored workers who either work outdoors or otherwise spend time outside 

buildings. Based on the exposure assessment, the two exposure pathways are: 

1. Inhalation of uranium in ambient air due to operational releases, 

2. Direct external radiation exposure from radionuclides in soils and outdoor surfaces, as well 

as shine from buildings and operational units. 

D.2 Intake of Radionuclides from On Site Releases of Radionuclides 

Although other radionuclides have been present at Y-12, the primary source of airborne radioactive 

material is uranium from the various operations that have occurred over the years. Thus, intakes 

have been calculated only for 234/235U and 238U. Only four monitoring stations are located on Y-12, so 

intakes have been calculated only for these locations (Tables D-1 to D-4). In addition, site-wide 

average concentrations based on the four stations have been calculated and are in Table D-5. The 

maximum intake is shown in Table D-6. 

The on site concentrations of 234/235U and 238U were estimated based on an empirical approach. The 

air concentrations and intakes were estimated using the 50th and 95th percentile values for the 

empirical dispersion coefficient (Chi/Q) for each station. Air concentrations (becquerel/cubic meter 

[Bq m-3]) for all years from 1944 to 2002 were estimated based on the quantities of uranium released. 

Intakes (Bq y-1) were estimated from the air concentrations based on an exposure assumption of 

2000 h y-1 and an inhalation rate of 1.2 m3

 h-1 . Intakes were estimated for four locations within the 

boundary of the facility. A site-wide average was also calculated from these four locations. In 

addition, maximum air concentrations and intakes are presented. 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 39 of 45 

Table D-1. Calculated 234/235U and 238U air concentrations and intakes for Station 2. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Station 2 Air Concentrations (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

4.41E-05 1.17E-04 2.02E-05 5.35E-05 

7.53E-05 1.99E-04 4.04E-05 1.07E-04 

5.69E-05 1.51E-04 2.39E-05 6.32E-05 

4.77E-05 1.26E-04 1.47E-05 3.89E-05 

3.12E-05 8.26E-05 4.04E-05 1.07E-04 

3.12E-05 8.26E-05 4.04E-05 1.07E-04 

3.12E-05 8.26E-05 4.04E-05 1.07E-04 

3.12E-05 8.26E-05 4.04E-05 1.07E-04 

3.12E-05 8.26E-05 4.04E-05 1.07E-04 

1.23E-04 3.26E-04 2.50E-04 6.61E-04 

1.06E-04 2.82E-04 2.35E-04 6.22E-04 

1.08E-04 2.87E-04 2.35E-04 6.22E-04 

5.88E-04 1.56E-03 1.84E-04 4.86E-04 

1.06E-03 2.82E-03 1.47E-04 3.89E-04 

3.19E-03 8.46E-03 3.30E-04 8.75E-04 

2.18E-03 5.78E-03 3.67E-04 9.72E-04 

4.46E-04 1.18E-03 5.69E-05 1.51E-04 

7.16E-04 1.90E-03 7.90E-05 2.09E-04 

7.73E-04 2.05E-03 8.45E-05 2.24E-04 

3.86E-04 1.02E-03 1.29E-04 3.40E-04 

1.25E-04 3.31E-04 1.67E-04 4.42E-04 

6.26E-04 1.66E-03 3.67E-05 9.72E-05 

2.00E-04 5.30E-04 5.69E-05 1.51E-04 

9.18E-05 2.43E-04 2.02E-05 5.35E-05 

4.04E-05 1.07E-04 2.75E-05 7.29E-05 

1.78E-04 4.71E-04 1.47E-05 3.89E-05 

2.92E-04 7.73E-04 1.65E-05 4.37E-05 

3.80E-04 1.01E-03 3.49E-05 9.24E-05 

6.72E-04 1.78E-03 5.14E-05 1.36E-04 

5.93E-04 1.57E-03 2.39E-05 6.32E-05 

5.14E-05 1.36E-04 1.29E-05 3.40E-05 

9.55E-05 2.53E-04 1.29E-05 3.40E-05 

6.06E-05 1.60E-04 1.29E-05 3.40E-05 

2.94E-05 7.78E-05 1.29E-05 3.40E-05 

3.12E-05 8.26E-05 1.29E-05 3.40E-05 

4.41E-05 1.17E-04 1.29E-05 3.40E-05 

8.63E-05 2.28E-04 1.29E-05 3.40E-05 

5.32E-05 1.41E-04 1.29E-05 3.40E-05 

8.81E-05 2.33E-04 1.29E-05 3.40E-05 

7.53E-05 1.99E-04 1.29E-05 3.40E-05 

6.43E-05 1.70E-04 2.02E-05 5.35E-05 

5.14E-05 1.36E-04 1.29E-05 3.40E-05 

6.43E-05 1.70E-04 1.29E-05 3.40E-05 

1.08E-04 2.87E-04 9.18E-06 2.43E-05 

5.51E-05 1.46E-04 9.18E-06 2.43E-05 

2.75E-05 7.29E-05 2.57E-06 6.80E-06 

1.47E-05 3.89E-05 1.29E-06 3.40E-06 

7.34E-06 1.94E-05 1.84E-06 4.86E-06 

7.34E-06 1.94E-05 1.10E-06 2.92E-06 

5.51E-06 1.46E-05 5.51E-07 1.46E-06 

5.51E-06 1.46E-05 3.67E-07 9.72E-07 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

3.67E-06 9.72E-06 3.86E-07 1.02E-06 

Station 2 Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.1058 0.2800 0.0485 0.1283 

0.1807 0.4783 0.0969 0.2566 

0.1366 0.3616 0.0573 0.1516 

0.1146 0.3033 0.0353 0.0933 

0.0749 0.1983 0.0969 0.2566 

0.0749 0.1983 0.0969 0.2566 

0.0749 0.1983 0.0969 0.2566 

0.0749 0.1983 0.0969 0.2566 

0.0749 0.1983 0.0969 0.2566 

0.2952 0.7816 0.5993 1.5865 

0.2556 0.6766 0.5640 1.4932 

0.2600 0.6883 0.5640 1.4932 

1.4101 3.7329 0.4407 1.1665 

2.5558 6.7659 0.3525 0.9332 

7.6674 20.2976 0.7932 2.0998 

5.2438 13.8817 0.8813 2.3331 

1.0708 2.8347 0.1366 0.3616 

1.7186 4.5495 0.1895 0.5016 

1.8552 4.9111 0.2027 0.5366 

0.9254 2.4497 0.3085 0.8166 

0.2996 0.7932 0.4010 1.0615 

1.5026 3.9779 0.0881 0.2333 

0.4803 1.2715 0.1366 0.3616 

0.2203 0.5833 0.0485 0.1283 

0.0969 0.2566 0.0661 0.1750 

0.4274 1.1315 0.0353 0.0933 

0.7006 1.8548 0.0397 0.1050 

0.9122 2.4147 0.0837 0.2216 

1.6128 4.2695 0.1234 0.3266 

1.4233 3.7679 0.0573 0.1516 

0.1234 0.3266 0.0308 0.0817 

0.2291 0.6066 0.0308 0.0817 

0.1454 0.3850 0.0308 0.0817 

0.0705 0.1866 0.0308 0.0817 

0.0749 0.1983 0.0308 0.0817 

0.1058 0.2800 0.0308 0.0817 

0.2071 0.5483 0.0308 0.0817 

0.1278 0.3383 0.0308 0.0817 

0.2115 0.5599 0.0308 0.0817 

0.1807 0.4783 0.0308 0.0817 

0.1542 0.4083 0.0485 0.1283 

0.1234 0.3266 0.0308 0.0817 

0.1542 0.4083 0.0308 0.0817 

0.2600 0.6883 0.0220 0.0583 

0.1322 0.3500 0.0220 0.0583 

0.0661 0.1750 0.0062 0.0163 

0.0353 0.0933 0.0031 0.0082 

0.0176 0.0467 0.0044 0.0117 

0.0176 0.0467 0.0026 0.0070 

0.0132 0.0350 0.0013 0.0035 

0.0132 0.0350 0.0009 0.0023 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 

0.0088 0.0233 0.0009 0.0024 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 40 of 45 

Table D-2. Calculated 234/235U and 238U air concentrations and intakes for Station 4. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Station 4 Air Concentration (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

1.28E-04 7.75E-04 5.87E-05 3.55E-04 

2.19E-04 1.32E-03 1.17E-04 7.11E-04 

1.65E-04 1.00E-03 6.93E-05 4.20E-04 

1.39E-04 8.40E-04 4.27E-05 2.58E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

3.57E-04 2.16E-03 7.25E-04 4.39E-03 

3.09E-04 1.87E-03 6.83E-04 4.13E-03 

3.15E-04 1.91E-03 6.83E-04 4.13E-03 

1.71E-03 1.03E-02 5.33E-04 3.23E-03 

3.09E-03 1.87E-02 4.27E-04 2.58E-03 

9.28E-03 5.62E-02 9.60E-04 5.81E-03 

6.35E-03 3.84E-02 1.07E-03 6.46E-03 

1.30E-03 7.85E-03 1.65E-04 1.00E-03 

2.08E-03 1.26E-02 2.29E-04 1.39E-03 

2.25E-03 1.36E-02 2.45E-04 1.49E-03 

1.12E-03 6.78E-03 3.73E-04 2.26E-03 

3.63E-04 2.20E-03 4.85E-04 2.94E-03 

1.82E-03 1.10E-02 1.07E-04 6.46E-04 

5.81E-04 3.52E-03 1.65E-04 1.00E-03 

2.67E-04 1.62E-03 5.87E-05 3.55E-04 

1.17E-04 7.11E-04 8.00E-05 4.85E-04 

5.17E-04 3.13E-03 4.27E-05 2.58E-04 

8.48E-04 5.14E-03 4.80E-05 2.91E-04 

1.10E-03 6.69E-03 1.01E-04 6.14E-04 

1.95E-03 1.18E-02 1.49E-04 9.05E-04 

1.72E-03 1.04E-02 6.93E-05 4.20E-04 

1.49E-04 9.05E-04 3.73E-05 2.26E-04 

2.77E-04 1.68E-03 3.73E-05 2.26E-04 

1.76E-04 1.07E-03 3.73E-05 2.26E-04 

8.53E-05 5.17E-04 3.73E-05 2.26E-04 

9.07E-05 5.49E-04 3.73E-05 2.26E-04 

1.28E-04 7.75E-04 3.73E-05 2.26E-04 

2.51E-04 1.52E-03 3.73E-05 2.26E-04 

1.55E-04 9.37E-04 3.73E-05 2.26E-04 

2.56E-04 1.55E-03 3.73E-05 2.26E-04 

2.19E-04 1.32E-03 3.73E-05 2.26E-04 

1.87E-04 1.13E-03 5.87E-05 3.55E-04 

1.49E-04 9.05E-04 3.73E-05 2.26E-04 

1.87E-04 1.13E-03 3.73E-05 2.26E-04 

3.15E-04 1.91E-03 2.67E-05 1.62E-04 

1.60E-04 9.69E-04 2.67E-05 1.62E-04 

8.00E-05 4.85E-04 7.47E-06 4.52E-05 

4.27E-05 2.58E-04 3.73E-06 2.26E-05 

2.13E-05 1.29E-04 5.33E-06 3.23E-05 

2.13E-05 1.29E-04 3.20E-06 1.94E-05 

1.60E-05 9.69E-05 1.60E-06 9.69E-06 

1.60E-05 9.69E-05 1.07E-06 6.46E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

Station 4 Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.3072 1.8607 0.1408 0.8528 

0.5247 3.1788 0.2816 1.7057 

0.3967 2.4035 0.1664 1.0079 

0.3328 2.0158 0.1024 0.6202 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.8575 5.1946 1.7406 10.5442 

0.7423 4.4968 1.6382 9.9239 

0.7551 4.5743 1.6382 9.9239 

4.0955 24.8098 1.2798 7.7531 

7.4230 44.9678 1.0239 6.2025 

22.2691 134.9034 2.3037 13.9555 

15.2300 92.2615 2.5597 15.5061 

3.1100 18.8400 0.3967 2.4035 

4.9914 30.2370 0.5503 3.3338 

5.3881 32.6404 0.5887 3.5664 

2.6877 16.2814 0.8959 5.4271 

0.8703 5.2721 1.1646 7.0553 

4.3642 26.4380 0.2560 1.5506 

1.3950 8.4508 0.3967 2.4035 

0.6399 3.8765 0.1408 0.8528 

0.2816 1.7057 0.1920 1.1630 

1.2414 7.5205 0.1024 0.6202 

2.0349 12.3274 0.1152 0.6978 

2.6493 16.0489 0.2432 1.4731 

4.6842 28.3762 0.3584 2.1709 

4.1339 25.0424 0.1664 1.0079 

0.3584 2.1709 0.0896 0.5427 

0.6655 4.0316 0.0896 0.5427 

0.4223 2.5585 0.0896 0.5427 

0.2048 1.2405 0.0896 0.5427 

0.2176 1.3180 0.0896 0.5427 

0.3072 1.8607 0.0896 0.5427 

0.6015 3.6439 0.0896 0.5427 

0.3712 2.2484 0.0896 0.5427 

0.6143 3.7215 0.0896 0.5427 

0.5247 3.1788 0.0896 0.5427 

0.4479 2.7136 0.1408 0.8528 

0.3584 2.1709 0.0896 0.5427 

0.4479 2.7136 0.0896 0.5427 

0.7551 4.5743 0.0640 0.3877 

0.3840 2.3259 0.0640 0.3877 

0.1920 1.1630 0.0179 0.1085 

0.1024 0.6202 0.0090 0.0543 

0.0512 0.3101 0.0128 0.0775 

0.0512 0.3101 0.0077 0.0465 

0.0384 0.2326 0.0038 0.0233 

0.0384 0.2326 0.0026 0.0155 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 41 of 45 

Table D-3. Calculated 234/235U and 238U air concentrations and intakes for Station 8. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Station 8 Air Concentration (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

1.12E-04 6.69E-04 5.12E-05 3.06E-04 

1.91E-04 1.14E-03 1.02E-04 6.13E-04 

1.44E-04 8.64E-04 6.05E-05 3.62E-04 

1.21E-04 7.24E-04 3.72E-05 2.23E-04 

7.91E-05 4.74E-04 1.02E-04 6.13E-04 

7.91E-05 4.74E-04 1.02E-04 6.13E-04 

7.91E-05 4.74E-04 1.02E-04 6.13E-04 

7.91E-05 4.74E-04 1.02E-04 6.13E-04 

7.91E-05 4.74E-04 1.02E-04 6.13E-04 

3.12E-04 1.87E-03 6.33E-04 3.79E-03 

2.70E-04 1.62E-03 5.96E-04 3.57E-03 

2.75E-04 1.64E-03 5.96E-04 3.57E-03 

1.49E-03 8.92E-03 4.65E-04 2.79E-03 

2.70E-03 1.62E-02 3.72E-04 2.23E-03 

8.10E-03 4.85E-02 8.37E-04 5.02E-03 

5.54E-03 3.32E-02 9.31E-04 5.57E-03 

1.13E-03 6.77E-03 1.44E-04 8.64E-04 

1.81E-03 1.09E-02 2.00E-04 1.20E-03 

1.96E-03 1.17E-02 2.14E-04 1.28E-03 

9.77E-04 5.85E-03 3.26E-04 1.95E-03 

3.16E-04 1.89E-03 4.23E-04 2.54E-03 

1.59E-03 9.50E-03 9.31E-05 5.57E-04 

5.07E-04 3.04E-03 1.44E-04 8.64E-04 

2.33E-04 1.39E-03 5.12E-05 3.06E-04 

1.02E-04 6.13E-04 6.98E-05 4.18E-04 

4.51E-04 2.70E-03 3.72E-05 2.23E-04 

7.40E-04 4.43E-03 4.19E-05 2.51E-04 

9.63E-04 5.77E-03 8.84E-05 5.29E-04 

1.70E-03 1.02E-02 1.30E-04 7.80E-04 

1.50E-03 9.00E-03 6.05E-05 3.62E-04 

1.30E-04 7.80E-04 3.26E-05 1.95E-04 

2.42E-04 1.45E-03 3.26E-05 1.95E-04 

1.54E-04 9.19E-04 3.26E-05 1.95E-04 

7.44E-05 4.46E-04 3.26E-05 1.95E-04 

7.91E-05 4.74E-04 3.26E-05 1.95E-04 

1.12E-04 6.69E-04 3.26E-05 1.95E-04 

2.19E-04 1.31E-03 3.26E-05 1.95E-04 

1.35E-04 8.08E-04 3.26E-05 1.95E-04 

2.23E-04 1.34E-03 3.26E-05 1.95E-04 

1.91E-04 1.14E-03 3.26E-05 1.95E-04 

1.63E-04 9.75E-04 5.12E-05 3.06E-04 

1.30E-04 7.80E-04 3.26E-05 1.95E-04 

1.63E-04 9.75E-04 3.26E-05 1.95E-04 

2.75E-04 1.64E-03 2.33E-05 1.39E-04 

1.40E-04 8.36E-04 2.33E-05 1.39E-04 

6.98E-05 4.18E-04 6.51E-06 3.90E-05 

3.72E-05 2.23E-04 3.26E-06 1.95E-05 

1.86E-05 1.11E-04 4.65E-06 2.79E-05 

1.86E-05 1.11E-04 2.79E-06 1.67E-05 

1.40E-05 8.36E-05 1.40E-06 8.36E-06 

1.40E-05 8.36E-05 9.31E-07 5.57E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

9.31E-06 5.57E-05 9.77E-07 5.85E-06 

Station 8 Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.2680 1.6048 0.1228 0.7356 

0.4578 2.7416 0.2457 1.4711 

0.3462 2.0729 0.1452 0.8693 

0.2903 1.7386 0.0893 0.5349 

0.1898 1.1368 0.2457 1.4711 

0.1898 1.1368 0.2457 1.4711 

0.1898 1.1368 0.2457 1.4711 

0.1898 1.1368 0.2457 1.4711 

0.1898 1.1368 0.2457 1.4711 

0.7482 4.4802 1.5187 9.0941 

0.6477 3.8784 1.4293 8.5592 

0.6588 3.9452 1.4293 8.5592 

3.5733 21.3979 1.1167 6.6869 

6.4766 38.7837 0.8933 5.3495 

19.4298 116.3512 2.0100 12.0363 

13.2882 79.5735 2.2333 13.3737 

2.7135 16.2490 0.3462 2.0729 

4.3550 26.0787 0.4802 2.8753 

4.7011 28.1516 0.5137 3.0760 

2.3450 14.0424 0.7817 4.6808 

0.7593 4.5471 1.0162 6.0850 

3.8078 22.8022 0.2233 1.3374 

1.2172 7.2887 0.3462 2.0729 

0.5583 3.3434 0.1228 0.7356 

0.2457 1.4711 0.1675 1.0030 

1.0832 6.4862 0.0893 0.5349 

1.7755 10.6321 0.1005 0.6018 

2.3115 13.8418 0.2122 1.2705 

4.0870 24.4739 0.3127 1.8723 

3.6068 21.5985 0.1452 0.8693 

0.3127 1.8723 0.0782 0.4681 

0.5807 3.4772 0.0782 0.4681 

0.3685 2.2067 0.0782 0.4681 

0.1787 1.0699 0.0782 0.4681 

0.1898 1.1368 0.0782 0.4681 

0.2680 1.6048 0.0782 0.4681 

0.5248 3.1428 0.0782 0.4681 

0.3238 1.9392 0.0782 0.4681 

0.5360 3.2097 0.0782 0.4681 

0.4578 2.7416 0.0782 0.4681 

0.3908 2.3404 0.1228 0.7356 

0.3127 1.8723 0.0782 0.4681 

0.3908 2.3404 0.0782 0.4681 

0.6588 3.9452 0.0558 0.3343 

0.3350 2.0061 0.0558 0.3343 

0.1675 1.0030 0.0156 0.0936 

0.0893 0.5349 0.0078 0.0468 

0.0447 0.2675 0.0112 0.0669 

0.0447 0.2675 0.0067 0.0401 

0.0335 0.2006 0.0033 0.0201 

0.0335 0.2006 0.0022 0.0134 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 

0.0223 0.1337 0.0023 0.0140 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 42 of 45 

Table D-4. Calculated 234/235U and 238U air concentrations and intakes for Station 12. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Station 12 Air Concentration (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

4.03E-05 1.70E-04 1.85E-05 7.81E-05 

6.88E-05 2.91E-04 3.69E-05 1.56E-04 

5.20E-05 2.20E-04 2.18E-05 9.23E-05 

4.36E-05 1.85E-04 1.34E-05 5.68E-05 

2.85E-05 1.21E-04 3.69E-05 1.56E-04 

2.85E-05 1.21E-04 3.69E-05 1.56E-04 

2.85E-05 1.21E-04 3.69E-05 1.56E-04 

2.85E-05 1.21E-04 3.69E-05 1.56E-04 

2.85E-05 1.21E-04 3.69E-05 1.56E-04 

1.12E-04 4.76E-04 2.28E-04 9.66E-04 

9.74E-05 4.12E-04 2.15E-04 9.09E-04 

9.90E-05 4.19E-04 2.15E-04 9.09E-04 

5.37E-04 2.27E-03 1.68E-04 7.10E-04 

9.74E-04 4.12E-03 1.34E-04 5.68E-04 

2.92E-03 1.24E-02 3.02E-04 1.28E-03 

2.00E-03 8.45E-03 3.36E-04 1.42E-03 

4.08E-04 1.73E-03 5.20E-05 2.20E-04 

6.55E-04 2.77E-03 7.22E-05 3.05E-04 

7.07E-04 2.99E-03 7.72E-05 3.27E-04 

3.53E-04 1.49E-03 1.18E-04 4.97E-04 

1.14E-04 4.83E-04 1.53E-04 6.46E-04 

5.72E-04 2.42E-03 3.36E-05 1.42E-04 

1.83E-04 7.74E-04 5.20E-05 2.20E-04 

8.39E-05 3.55E-04 1.85E-05 7.81E-05 

3.69E-05 1.56E-04 2.52E-05 1.06E-04 

1.63E-04 6.89E-04 1.34E-05 5.68E-05 

2.67E-04 1.13E-03 1.51E-05 6.39E-05 

3.48E-04 1.47E-03 3.19E-05 1.35E-04 

6.14E-04 2.60E-03 4.70E-05 1.99E-04 

5.42E-04 2.29E-03 2.18E-05 9.23E-05 

4.70E-05 1.99E-04 1.18E-05 4.97E-05 

8.73E-05 3.69E-04 1.18E-05 4.97E-05 

5.54E-05 2.34E-04 1.18E-05 4.97E-05 

2.69E-05 1.14E-04 1.18E-05 4.97E-05 

2.85E-05 1.21E-04 1.18E-05 4.97E-05 

4.03E-05 1.70E-04 1.18E-05 4.97E-05 

7.89E-05 3.34E-04 1.18E-05 4.97E-05 

4.87E-05 2.06E-04 1.18E-05 4.97E-05 

8.06E-05 3.41E-04 1.18E-05 4.97E-05 

6.88E-05 2.91E-04 1.18E-05 4.97E-05 

5.88E-05 2.48E-04 1.85E-05 7.81E-05 

4.70E-05 1.99E-04 1.18E-05 4.97E-05 

5.88E-05 2.48E-04 1.18E-05 4.97E-05 

9.90E-05 4.19E-04 8.39E-06 3.55E-05 

5.04E-05 2.13E-04 8.39E-06 3.55E-05 

2.52E-05 1.06E-04 2.35E-06 9.94E-06 

1.34E-05 5.68E-05 1.18E-06 4.97E-06 

6.72E-06 2.84E-05 1.68E-06 7.10E-06 

6.72E-06 2.84E-05 1.01E-06 4.26E-06 

5.04E-06 2.13E-05 5.04E-07 2.13E-06 

5.04E-06 2.13E-05 3.36E-07 1.42E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

3.36E-06 1.42E-05 3.53E-07 1.49E-06 

Station 12 Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.0967 0.4089 0.0443 0.1874 

0.1652 0.6986 0.0886 0.3748 

0.1249 0.5282 0.0524 0.2215 

0.1048 0.4430 0.0322 0.1363 

0.0685 0.2897 0.0886 0.3748 

0.0685 0.2897 0.0886 0.3748 

0.0685 0.2897 0.0886 0.3748 

0.0685 0.2897 0.0886 0.3748 

0.0685 0.2897 0.0886 0.3748 

0.2700 1.1416 0.5480 2.3172 

0.2337 0.9882 0.5157 2.1809 

0.2377 1.0053 0.5157 2.1809 

1.2893 5.4523 0.4029 1.7039 

2.3369 9.8824 0.3223 1.3631 

7.0107 29.6471 0.7252 3.0669 

4.7947 20.2759 0.8058 3.4077 

0.9791 4.1404 0.1249 0.5282 

1.5714 6.6450 0.1733 0.7327 

1.6963 7.1732 0.1853 0.7838 

0.8461 3.5781 0.2820 1.1927 

0.2740 1.1586 0.3667 1.5505 

1.3739 5.8102 0.0806 0.3408 

0.4392 1.8572 0.1249 0.5282 

0.2015 0.8519 0.0443 0.1874 

0.0886 0.3748 0.0604 0.2556 

0.3908 1.6527 0.0322 0.1363 

0.6406 2.7091 0.0363 0.1533 

0.8340 3.5270 0.0766 0.3237 

1.4747 6.2361 0.1128 0.4771 

1.3014 5.5035 0.0524 0.2215 

0.1128 0.4771 0.0282 0.1193 

0.2095 0.8860 0.0282 0.1193 

0.1330 0.5623 0.0282 0.1193 

0.0645 0.2726 0.0282 0.1193 

0.0685 0.2897 0.0282 0.1193 

0.0967 0.4089 0.0282 0.1193 

0.1894 0.8008 0.0282 0.1193 

0.1168 0.4941 0.0282 0.1193 

0.1934 0.8179 0.0282 0.1193 

0.1652 0.6986 0.0282 0.1193 

0.1410 0.5964 0.0443 0.1874 

0.1128 0.4771 0.0282 0.1193 

0.1410 0.5964 0.0282 0.1193 

0.2377 1.0053 0.0201 0.0852 

0.1209 0.5112 0.0201 0.0852 

0.0604 0.2556 0.0056 0.0239 

0.0322 0.1363 0.0028 0.0119 

0.0161 0.0682 0.0040 0.0170 

0.0161 0.0682 0.0024 0.0102 

0.0121 0.0511 0.0012 0.0051 

0.0121 0.0511 0.0008 0.0034 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 

0.0081 0.0341 0.0008 0.0036 
Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 43 of 45 

Table D-5. Site wide 234/235U and 238U air concentrations and intakes based on average air 

concentrations for Stations 2, 4, 8 and 12. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Site Wide Average Air Concentration (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

8.10E-05 4.33E-04 3.71E-05 1.98E-04 

1.38E-04 7.39E-04 7.43E-05 3.97E-04 

1.05E-04 5.59E-04 4.39E-05 2.34E-04 

8.78E-05 4.69E-04 2.70E-05 1.44E-04 

5.74E-05 3.07E-04 7.43E-05 3.97E-04 

5.74E-05 3.07E-04 7.43E-05 3.97E-04 

5.74E-05 3.07E-04 7.43E-05 3.97E-04 

5.74E-05 3.07E-04 7.43E-05 3.97E-04 

5.74E-05 3.07E-04 7.43E-05 3.97E-04 

2.26E-04 1.21E-03 4.59E-04 2.45E-03 

1.96E-04 1.05E-03 4.32E-04 2.31E-03 

1.99E-04 1.06E-03 4.32E-04 2.31E-03 

1.08E-03 5.77E-03 3.38E-04 1.80E-03 

1.96E-03 1.05E-02 2.70E-04 1.44E-03 

5.87E-03 3.14E-02 6.08E-04 3.25E-03 

4.02E-03 2.15E-02 6.75E-04 3.61E-03 

8.20E-04 4.38E-03 1.05E-04 5.59E-04 

1.32E-03 7.03E-03 1.45E-04 7.75E-04 

1.42E-03 7.59E-03 1.55E-04 8.29E-04 

7.09E-04 3.79E-03 2.36E-04 1.26E-03 

2.30E-04 1.23E-03 3.07E-04 1.64E-03 

1.15E-03 6.15E-03 6.75E-05 3.61E-04 

3.68E-04 1.97E-03 1.05E-04 5.59E-04 

1.69E-04 9.02E-04 3.71E-05 1.98E-04 

7.43E-05 3.97E-04 5.06E-05 2.70E-04 

3.27E-04 1.75E-03 2.70E-05 1.44E-04 

5.37E-04 2.87E-03 3.04E-05 1.62E-04 

6.99E-04 3.73E-03 6.41E-05 3.43E-04 

1.24E-03 6.60E-03 9.45E-05 5.05E-04 

1.09E-03 5.82E-03 4.39E-05 2.34E-04 

9.45E-05 5.05E-04 2.36E-05 1.26E-04 

1.76E-04 9.38E-04 2.36E-05 1.26E-04 

1.11E-04 5.95E-04 2.36E-05 1.26E-04 

5.40E-05 2.89E-04 2.36E-05 1.26E-04 

5.74E-05 3.07E-04 2.36E-05 1.26E-04 

8.10E-05 4.33E-04 2.36E-05 1.26E-04 

1.59E-04 8.47E-04 2.36E-05 1.26E-04 

9.79E-05 5.23E-04 2.36E-05 1.26E-04 

1.62E-04 8.66E-04 2.36E-05 1.26E-04 

1.38E-04 7.39E-04 2.36E-05 1.26E-04 

1.18E-04 6.31E-04 3.71E-05 1.98E-04 

9.45E-05 5.05E-04 2.36E-05 1.26E-04 

1.18E-04 6.31E-04 2.36E-05 1.26E-04 

1.99E-04 1.06E-03 1.69E-05 9.02E-05 

1.01E-04 5.41E-04 1.69E-05 9.02E-05 

5.06E-05 2.70E-04 4.73E-06 2.52E-05 

2.70E-05 1.44E-04 2.36E-06 1.26E-05 

1.35E-05 7.21E-05 3.38E-06 1.80E-05 

1.35E-05 7.21E-05 2.03E-06 1.08E-05 

1.01E-05 5.41E-05 1.01E-06 5.41E-06 

1.01E-05 5.41E-05 6.75E-07 3.61E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

6.75E-06 3.61E-05 7.09E-07 3.79E-06 

Site Wide Average Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.1944 1.0386 0.0891 0.4760 

0.3321 1.7743 0.1782 0.9521 

0.2511 1.3415 0.1053 0.5626 

0.2106 1.1252 0.0648 0.3462 

0.1377 0.7357 0.1782 0.9521 

0.1377 0.7357 0.1782 0.9521 

0.1377 0.7357 0.1782 0.9521 

0.1377 0.7357 0.1782 0.9521 

0.1377 0.7357 0.1782 0.9521 

0.5427 2.8995 1.1016 5.8855 

0.4698 2.5100 1.0368 5.5393 

0.4779 2.5533 1.0368 5.5393 

2.5920 13.8482 0.8100 4.3276 

4.6981 25.0999 0.6480 3.4621 

14.0943 75.2998 1.4580 7.7896 

9.6392 51.4982 1.6200 8.6552 

1.9683 10.5160 0.2511 1.3415 

3.1591 16.8775 0.3483 1.8609 

3.4102 18.2191 0.3726 1.9907 

1.7010 9.0879 0.5670 3.0293 

0.5508 2.9428 0.7371 3.9381 

2.7621 14.7570 0.1620 0.8655 

0.8829 4.7171 0.2511 1.3415 

0.4050 2.1638 0.0891 0.4760 

0.1782 0.9521 0.1215 0.6491 

0.7857 4.1977 0.0648 0.3462 

1.2879 6.8808 0.0729 0.3895 

1.6767 8.9581 0.1539 0.8222 

2.9647 15.8389 0.2268 1.2117 

2.6163 13.9781 0.1053 0.5626 

0.2268 1.2117 0.0567 0.3029 

0.4212 2.2503 0.0567 0.3029 

0.2673 1.4281 0.0567 0.3029 

0.1296 0.6924 0.0567 0.3029 

0.1377 0.7357 0.0567 0.3029 

0.1944 1.0386 0.0567 0.3029 

0.3807 2.0340 0.0567 0.3029 

0.2349 1.2550 0.0567 0.3029 

0.3888 2.0772 0.0567 0.3029 

0.3321 1.7743 0.0567 0.3029 

0.2835 1.5147 0.0891 0.4760 

0.2268 1.2117 0.0567 0.3029 

0.2835 1.5147 0.0567 0.3029 

0.4779 2.5533 0.0405 0.2164 

0.2430 1.2983 0.0405 0.2164 

0.1215 0.6491 0.0113 0.0606 

0.0648 0.3462 0.0057 0.0303 

0.0324 0.1731 0.0081 0.0433 

0.0324 0.1731 0.0049 0.0260 

0.0243 0.1298 0.0024 0.0130 

0.0243 0.1298 0.0016 0.0087 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 

0.0162 0.0866 0.0017 0.0091 
 

 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 44 of 45 

Table D-6. Maximum 234/235U and 238U air concentrations and intakes. 

YEAR 

1944 

1945 

1946 

1947 

1948 

1949 

1950 

1951 

1952 

1953 

1954 

1955 

1956 

1957 

1958 

1959 

1960 

1961 

1962 

1963 

1964 

1965 

1966 

1967 

1968 

1969 

1970 

1971 

1972 

1973 

1974 

1975 

1976 

1977 

1978 

1979 

1980 

1981 

1982 

1983 

1984 

1985 

1986 

1987 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 

2001 

2002 

Station 4 Air Concentration (Bq m-3) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

1.28E-04 7.75E-04 5.87E-05 3.55E-04 

2.19E-04 1.32E-03 1.17E-04 7.11E-04 

1.65E-04 1.00E-03 6.93E-05 4.20E-04 

1.39E-04 8.40E-04 4.27E-05 2.58E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

9.07E-05 5.49E-04 1.17E-04 7.11E-04 

3.57E-04 2.16E-03 7.25E-04 4.39E-03 

3.09E-04 1.87E-03 6.83E-04 4.13E-03 

3.15E-04 1.91E-03 6.83E-04 4.13E-03 

1.71E-03 1.03E-02 5.33E-04 3.23E-03 

3.09E-03 1.87E-02 4.27E-04 2.58E-03 

9.28E-03 5.62E-02 9.60E-04 5.81E-03 

6.35E-03 3.84E-02 1.07E-03 6.46E-03 

1.30E-03 7.85E-03 1.65E-04 1.00E-03 

2.08E-03 1.26E-02 2.29E-04 1.39E-03 

2.25E-03 1.36E-02 2.45E-04 1.49E-03 

1.12E-03 6.78E-03 3.73E-04 2.26E-03 

3.63E-04 2.20E-03 4.85E-04 2.94E-03 

1.82E-03 1.10E-02 1.07E-04 6.46E-04 

5.81E-04 3.52E-03 1.65E-04 1.00E-03 

2.67E-04 1.62E-03 5.87E-05 3.55E-04 

1.17E-04 7.11E-04 8.00E-05 4.85E-04 

5.17E-04 3.13E-03 4.27E-05 2.58E-04 

8.48E-04 5.14E-03 4.80E-05 2.91E-04 

1.10E-03 6.69E-03 1.01E-04 6.14E-04 

1.95E-03 1.18E-02 1.49E-04 9.05E-04 

1.72E-03 1.04E-02 6.93E-05 4.20E-04 

1.49E-04 9.05E-04 3.73E-05 2.26E-04 

2.77E-04 1.68E-03 3.73E-05 2.26E-04 

1.76E-04 1.07E-03 3.73E-05 2.26E-04 

8.53E-05 5.17E-04 3.73E-05 2.26E-04 

9.07E-05 5.49E-04 3.73E-05 2.26E-04 

1.28E-04 7.75E-04 3.73E-05 2.26E-04 

2.51E-04 1.52E-03 3.73E-05 2.26E-04 

1.55E-04 9.37E-04 3.73E-05 2.26E-04 

2.56E-04 1.55E-03 3.73E-05 2.26E-04 

2.19E-04 1.32E-03 3.73E-05 2.26E-04 

1.87E-04 1.13E-03 5.87E-05 3.55E-04 

1.49E-04 9.05E-04 3.73E-05 2.26E-04 

1.87E-04 1.13E-03 3.73E-05 2.26E-04 

3.15E-04 1.91E-03 2.67E-05 1.62E-04 

1.60E-04 9.69E-04 2.67E-05 1.62E-04 

8.00E-05 4.85E-04 7.47E-06 4.52E-05 

4.27E-05 2.58E-04 3.73E-06 2.26E-05 

2.13E-05 1.29E-04 5.33E-06 3.23E-05 

2.13E-05 1.29E-04 3.20E-06 1.94E-05 

1.60E-05 9.69E-05 1.60E-06 9.69E-06 

1.60E-05 9.69E-05 1.07E-06 6.46E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

1.07E-05 6.46E-05 1.12E-06 6.78E-06 

Station 4 Intake (Bq y-1) 234/235U 238U 

50th 

Percentile 

95th 

Percentile 

50th 

Percentile 

95th 

Percentile 

0.3072 1.8607 0.1408 0.8528 

0.5247 3.1788 0.2816 1.7057 

0.3967 2.4035 0.1664 1.0079 

0.3328 2.0158 0.1024 0.6202 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.2176 1.3180 0.2816 1.7057 

0.8575 5.1946 1.7406 10.5442 

0.7423 4.4968 1.6382 9.9239 

0.7551 4.5743 1.6382 9.9239 

4.0955 24.8098 1.2798 7.7531 

7.4230 44.9678 1.0239 6.2025 

22.2691 134.9034 2.3037 13.9555 

15.2300 92.2615 2.5597 15.5061 

3.1100 18.8400 0.3967 2.4035 

4.9914 30.2370 0.5503 3.3338 

5.3881 32.6404 0.5887 3.5664 

2.6877 16.2814 0.8959 5.4271 

0.8703 5.2721 1.1646 7.0553 

4.3642 26.4380 0.2560 1.5506 

1.3950 8.4508 0.3967 2.4035 

0.6399 3.8765 0.1408 0.8528 

0.2816 1.7057 0.1920 1.1630 

1.2414 7.5205 0.1024 0.6202 

2.0349 12.3274 0.1152 0.6978 

2.6493 16.0489 0.2432 1.4731 

4.6842 28.3762 0.3584 2.1709 

4.1339 25.0424 0.1664 1.0079 

0.3584 2.1709 0.0896 0.5427 

0.6655 4.0316 0.0896 0.5427 

0.4223 2.5585 0.0896 0.5427 

0.2048 1.2405 0.0896 0.5427 

0.2176 1.3180 0.0896 0.5427 

0.3072 1.8607 0.0896 0.5427 

0.6015 3.6439 0.0896 0.5427 

0.3712 2.2484 0.0896 0.5427 

0.6143 3.7215 0.0896 0.5427 

0.5247 3.1788 0.0896 0.5427 

0.4479 2.7136 0.1408 0.8528 

0.3584 2.1709 0.0896 0.5427 

0.4479 2.7136 0.0896 0.5427 

0.7551 4.5743 0.0640 0.3877 

0.3840 2.3259 0.0640 0.3877 

0.1920 1.1630 0.0179 0.1085 

0.1024 0.6202 0.0090 0.0543 

0.0512 0.3101 0.0128 0.0775 

0.0512 0.3101 0.0077 0.0465 

0.0384 0.2326 0.0038 0.0233 

0.0384 0.2326 0.0026 0.0155 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 

0.0256 0.1551 0.0027 0.0163 
D.3 

Effective Date: 12/05/2003 Revision No. 00 Document No. ORAUT-TKBS-0014-4 Page 45 of 45 

Ambient External Dose 

Ambient radiation levels will be typically measured by the monitored worker’s personal dosimeters. 

However, for the unmonitored worker, external radiation exposures were estimated from prior 

characterization efforts at Y-12. 

There are two potential sources of external exposures received by workers at the Y-12 facility: 

1. Exposures from the deposition of radionuclides released as a consequence of facility 

operations, 

2. Exposures received from radiation levels emanating from buildings and storage areas. 

The data from the scoping survey should be used to calculate an external dose for unmonitored 

workers (Foley and Carrier 1990). The dose rates shown in Table D-7 represent the external 

exposure rates measured site wide. The exposure rates were converted to dose equivalent rates 

assuming a quality factor of one (1). 

Table D-7. External dose rates outside buildings on Y-12 site. 

Measured 

exposure rate Dose rate excluding 

(μR h-1) background (mrem h-1) 

Minimum 4 0 

Maximum 1500 1492 

Geometric Mean (GM) 21 13 

Geometric Standard Deviation (GSD) 3.0 

50th Percentile 21 13 

95th Percentile 129 121